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SQL Multiple Choice Questions & Answers – JOINS

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Welcome to the SQL Quiz! This blog post features 25 multiple-choice questions that explore JOINS concept of SQL.

1. Which SQL JOIN returns only the rows that have matching values in both tables?

a) LEFT JOIN
b) RIGHT JOIN
c) INNER JOIN
d) FULL OUTER JOIN

Answer 1

c) INNER JOIN

INNER JOIN matches records in both tables based on the join condition.

2. What does the following SQL query return?

SELECT products.product_name, orders.order_date
FROM products
INNER JOIN orders ON products.product_id = orders.product_id;

a) Only products that have been ordered
b) All products, ordered and non-ordered
c) All orders, regardless of the products
d) None of the above

Answer 2

a) Only products that have been ordered

The INNER JOIN retrieves only products that have corresponding order records.

3. If you want all rows from the left table and only the matching rows from the right table, which join will you use?

a) INNER JOIN
b) RIGHT JOIN
c) LEFT JOIN
d) FULL JOIN

Answer 3

c) LEFT JOIN

LEFT JOIN keeps all rows from the left table and adds NULLs for non-matching right table rows.

4. Which join type would you use to include all students and their respective grades, whether or not the grades are recorded?

SELECT students.student_name, grades.grade
FROM students
__________ JOIN grades ON students.student_id = grades.student_id;

a) INNER JOIN
b) RIGHT JOIN
c) LEFT JOIN
d) FULL JOIN

Answer 4

c) LEFT JOIN

A LEFT JOIN includes all students and their grades, with NULL for students without recorded grades.

5. Which JOIN includes all records from both tables, filling NULLs where there are no matches?

a) INNER JOIN
b) CROSS JOIN
c) FULL OUTER JOIN
d) SELF JOIN

Answer 5

c) FULL OUTER JOIN

FULL OUTER JOIN returns all rows from both tables with NULLs where no match exists.

6. What result does the following query produce?

SELECT a.name, b.address
FROM customers a
FULL OUTER JOIN orders b ON a.customer_id = b.customer_id;

a) Only matching customers and orders
b) All customers and orders with matches and non-matches
c) Customers without orders
d) Orders without customers

Answer 6

b) All customers and orders with matches and non-matches

A FULL OUTER JOIN returns all records when there is a match in either table A or table B.

7. What does a CROSS JOIN do?

a) Matches only the common records
b) Returns Cartesian product of two tables
c) Returns only distinct records
d) Works only on primary keys

Answer 7

b) Returns Cartesian product of two tables

CROSS JOIN multiplies all rows from one table with all rows of another.

8. What does the following SQL query do?

SELECT e.employee_id, e.name, d.department_name
FROM employees e
CROSS JOIN departments d;

a) Joins each employee with all departments
b) Returns only matched employees and departments
c) Lists employees without departments
d) Lists departments without employees

Answer 8

a) Joins each employee with all departments

A CROSS JOIN creates a Cartesian product of both tables.

9. Which JOIN is used to join a table with itself?

a) CROSS JOIN
b) SELF JOIN
c) FULL OUTER JOIN
d) NATURAL JOIN

Answer 9

b) SELF JOIN

SELF JOIN is useful for hierarchical or recursive relationships.

10. What is a primary use case for a self join in SQL?

a) To join two unrelated databases
b) To compare rows within the same table
c) To join tables with similar schemas
d) To execute subqueries

Answer 10

b) To compare rows within the same table

SELECT a.employee_id, a.name, b.manager_id
FROM employees a
JOIN employees b ON a.manager_id = b.employee_id;

In the provided query, the employees table is joined with itself to find employees and their respective managers by matching employee IDs with manager IDs.

11. In a self join scenario, how would you distinguish between the different roles of the table being joined to itself?

Choose one option

a) Use different database instances
b) Use table aliases
c) Create a temporary table
d) Use a different SQL dialect

Answer 11

b) Use table aliases

SELECT e1.name AS Employee, e2.name AS Manager
FROM employees e1
JOIN employees e2 ON e1.manager_id = e2.employee_id;

In a self join, table aliases are employed to differentiate between the roles of the same table. Here, `e1` represents employees, and `e2` represents managers, allowing us to fetch the employee names along with their corresponding managers.

12.  To avoid a Cartesian product, always include a valid join condition in a WHERE clause.

Choose one option

a) True
b) False

Answer 12

a) True

If we don’t use WHERE clause in a join, it will do a cartesian product.

13. Which type of JOIN is used to select all records from the right table and the matched records from the left table?

Choose one option

a) OUTER JOIN
b) SELF JOIN
c) RIGHT JOIN
d) NATURAL JOIN

Answer 13

c) RIGHT JOIN

A RIGHT JOIN returns all records from the right table and the matched records from the left table. Unmatched left table records receive NULLs.

14. Given the tables employees and departments, which query will list all department names even if they have no employees?

Choose one option

a) LEFT JOIN
b) SELF JOIN
c) RIGHT JOIN
d) INNER JOIN

Answer 14

c) RIGHT JOIN

SELECT departments.department_name, employees.name
FROM departments
RIGHT JOIN employees ON departments.id = employees.department_id;

The RIGHT JOIN returns all department names, including those with no associated employees.

15. Can multiple JOIN operations be used in a single SQL query?

Choose one option

a) True
b) False

Answer 15

a) True

Multiple JOIN operations can be utilized in a single query to combine data from more than two tables.

16. In a SQL JOIN, what does the ON keyword do?

Choose one option

a) Specifies the columns for joining
b) Specifies the conditions for joining
c) Specifies the number of rows to return
d) Specifies the order of columns

Answer 16

b) Specifies the conditions for joining

The ON keyword specifies conditions that determine which rows are retrieved in the join operation.

17.  To combine data from multiple tables where relationships exist, which SQL feature should be used besides JOINs?

Choose one option

a) Subqueries
b) Cursors
c) Triggers
d) Indexes

Answer 17

a) Subqueries

Subqueries can be used to combine data or perform operations that retrieve data from multiple tables based on conditions.

18.  What is a NATURAL JOIN based on?

a) Explicit conditions
b) Common columns automatically determined
c) Primary keys
d) Foreign keys

Answer 18

b) Common columns automatically determined

A NATURAL JOIN automatically joins tables based on columns with matching names and compatible data types.

 19.  Below two tables (A & B) are given.

What will be the result of inner join between these tables?

a) 1,3,4
b) 1,2,3,4,5,6,7,8,9,10,12
c) 1,2,3,4,5,6,7
d) 1,3,4,8,9,10,12

Answer 19

a) 1,3,4

20. What will be the result of FULL OUTER JOIN between these tables?

Choose one option

a) 1,3,4
b) 1,2,3,4,5,6,7,8,9,10,12
c) 1,2,3,4,5,6,7
d) 1,3,4,8,9,10,12

Answer 20

b) 1,2,3,4,5,6,7,8,9,10,12

21. Select the correct query/queries for cross join:

a) Select * FROM Table1 T1 CROSS JOIN Table1 T2;
b) Select * FROM Table1 T1 ALL CROSS JOIN Table1 T2;
c) Select * FROM Table1 T1,Table1 T2;
d) Select * FROM Table1 T1 CROSS Table1 T2;
Answer 21

a) Select * FROM Table1 T1 CROSS JOIN Table1 T2;

22. Which clause can be used with a JOIN to filter records?

a) WHERE
b) HAVING
c) GROUP BY
d) ORDER BY

Answer 22

a) WHERE

The WHERE clause can be used to filter records after the JOIN operation, whereas HAVING is typically used with GROUP BY.

23. How can SQL JOINs be optimized for better performance?

a) Using indexes on join columns
b) Avoiding WHERE clauses
c) Using more complex joins
d) Increasing database storage

Answer 23

a) Using indexes on join columns

Optimizing SQL JOIN performance generally involves using indexes on the columns involved in the join conditions.

24. Consider the tables `students` and `enrollments`, both having the column `student_id`. What will the following SQL statement do?

SELECT * FROM students NATURAL JOIN enrollments;

a) Join using all columns that are common between the two tables
b) Require user to specify a join condition
c) Join using columns named `student_id`
d) Join with duplicate column names represented multiple times

Answer 24

c) Join using columns named `student_id`

The NATURAL JOIN will operate on all columns with the same name, joining on `student_id` as it’s the common column between `students` and `enrollments`.

25. What is a potential disadvantage of using NATURAL JOIN?

a) It is only available in a few SQL dialects
b) Can join tables that have no related columns
c) Lacks explicit control over join conditions
d) Always results in Cartesian product of the tables

Answer 25

c) Lacks explicit control over join conditions

NATURAL JOIN does not allow you to specify which common columns to use for joining, which can lead to unforeseen results if multiple columns share the same name across tables.

We would love to hear from you! Please leave your comments and share your scores in the section below

vibssingh

SpringBoot – Multiple Choice Questions and Answers – MCQ2

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Welcome to the SpringBoot Quiz! This article delves into the essential concepts and features of Spring Boot. It covers annotations, configuration properties, and metrics. The article also discusses caching mechanisms and shares best practices for building robust applications.

1. Which of the following is true about Spring Boot?

a) Spring Boot is a separate framework and not a part of the Spring ecosystem
b) Spring Boot requires manual configuration for every aspect of the application
c) Spring Boot simplifies the development of Spring applications by providing an opinionated approach and auto-configuration
d) Spring Boot is only suitable for small-scale applications with limited functionality

Answer 1

c) Spring Boot simplifies the development of Spring applications by providing an opinionated approach and auto-configuration

Spring Boot simplifies the development of new Spring applications through convention over configuration and automatic setup. Spring Boot eliminates the need for manual configuration. It provides sensible defaults. It also offers automatic configuration based on classpath scanning and dependency management. 

2. What is the purpose of the @ConfigurationProperties annotation?

@ConfigurationProperties(prefix = "app")
public class AppConfig {
      private String name;
      private String version;
     // Getters and setters
}

a) It defines a bean with a specific name.
b) It maps properties to a class.
c) It creates a REST controller.
d) It handles exceptions.

Answer 2

b) It maps properties to a class.

The @ConfigurationProperties annotation is used to bind external properties (e.g., those defined in application.properties or application.yml) to fields in a Java class. In the example provided, properties with keys like “app.name” and “app.version” would be mapped to the fields `name` and `version` in the `AppConfig` class.

3. Which of the following statements is true about the @Autowired annotation in Spring Boot?

a) @Autowired is used to inject dependencies into Spring Boot applications
b) @Autowired is only applicable for injecting dependencies of type String
c) @Autowired is optional and not required for dependency injection in Spring Boot
d) @Autowired is mandatory in Spring Boot and can only be used in service classes

Answer 3

a) @Autowired is used to inject dependencies into Spring Boot applications

Autowired is used to inject dependencies into Spring Boot applications. With Autowired annotation, dependencies can be automatically injected into the dependent class by Springs dependency injection mechanism.

4. What does the @Autowired annotation do in the following code?

@Service
public class ArticleService {
    @Autowired
    private ArticleRepository articleRepository;
}

a) It creates a new instance of ArticleRepository.
b) It injects an existing instance of ArticleRepository
c) It defines a REST endpoint
d) It marks the class as a Spring component

Answer 4

b) It injects an existing instance of ArticleRepository

The @Autowired annotation is used to inject an existing instance of the ArticleRepository into the ArticleService

5. Which annotation is used to automatically configure a Spring Boot application for RESTful services?

a) @RestController
b) @Service
c) @Repository
d) @Component

Answer 5

a) @RestController

The @RestController annotation is used to define a controller that handles RESTful web service requests.

6. Which of the following code snippets demonstrates the correct configuration of a Spring Boot REST Controller?

a) 

@RestController
public class MyController {

    @GetMapping("/hello")
    public String hello() {
        return "Hello, World!";
    }
}


b) 

@Controller
@RequestMapping("/api")
public class MyController {

    @GetMapping("/hello")
    public String hello() {
        return "Hello, World!";
    }
}


c) 

@RestController
@RequestMapping("/api")
public class MyController {

    @RequestMapping("/hello")
    public String hello() {
        return "Hello, World!";
    }
}


d) 

@Controller
public class MyController {

    @RequestMapping(value = "/hello", method = RequestMethod.GET)
    @ResponseBody
    public String hello() {
        return "Hello, World!";
    }
}
Answer 6

Option a) has the correct configuration for a Spring Boot REST Controller utilizing the simplified annotations that Spring provides

Options b) and d) use @Controller which would require @ResponseBody for RESTful outputs if not using @RestController. Option c) incorrectly utilizes @RequestMapping instead of @GetMapping for the GET request.

7. Which of the following code snippets demonstrates the correct configuration of a Spring Boot application class?

a) 

@Configuration
public class MyApp {
    public static void main(String[] args) {
        SpringApplication.run(MyApp.class, args);
    }
}

b) 

@SpringBootApplication
public class MyApp {
    public static void main(String[] args) {
        SpringApplication.run(MyApp.class, args);
    }
}


c) 

@RestController
public class MyApp {
    public static void main(String[] args) {
        SpringApplication.run(MyApp.class, args);
    }
}

d)

@Component
public class MyApp {
    public static void main(String[] args) {
        SpringApplication.run(MyApp.class, args);
    }
}
Answer 7

Option b) demonstrates the correct configuration of a Spring Boot application class. The @SpringBootApplication annotation is used to mark the class as the main application class in Spring Boot.

8. What is the purpose of the @Cacheable annotation?

@Cacheable("articles")
public Article getArticleById(Long id) {
    return articleRepository.findById(id).orElse(null);
}

a) It stores the result in the database
b) It caches the method’s result
c) It logs the method’s execution time
d) It defines a scheduled task

Answer 8

b) It caches the method’s result

The @Cacheable annotation caches the result of the method call, so subsequent calls with the same parameters can return the cached result.

9. In the context of Spring Boot, what does @SpringBootTest annotation do?

a) It is used to run unit tests only
b) It loads the complete application context for integration tests
c) It defines a REST endpoint for testing
d) It initializes application properties

Answer 9

b) It loads the complete application context for integration tests

The @SpringBootTest annotation is used to create an application context for integration tests, allowing the entire application to be tested as a whole

10. What type of object is returned by a Spring Boot REST endpoint when using ResponseEntity?

a) A plain Java object
b) A JSON string
c) An HTTP response with status and body
d) A configuration property

Answer 10

c) An HTTP response with status and body

The ResponseEntity class represents an HTTP response, including status code, headers, and body

11. How do you specify an endpoint that accepts JSON data in a POST request?

@PostMapping("/articles")
public ResponseEntity<Article> createArticle(@RequestBody Article article) {
    // Save article logic
    return ResponseEntity.status(HttpStatus.CREATED).body(savedArticle);
}

Choose one option

a) The endpoint only accepts URL-encoded data
b) The method uses @RequestBody to map the request body to an Article object
c) The endpoint does not return any response
d) The method automatically handles validation

Answer 11

b) The method uses @RequestBody to map the request body to an Article object

 The @RequestBody annotation binds the JSON data from the request body to the Article object

12.  How do you disable a specific auto-configuration class in Spring Boot?

Choose one option

a) Set auto-configuration.enabled: false for the class
b) Use the @DisableAutoConfiguration annotation
c) Manually exclude the class from the application context
d) Use the exclude attribute of @SpringBootApplication annotation

Answer 12

d) Use the exclude attribute of @SpringBootApplication annotation

The exclude attribute allows specifying auto-configuration classes to be excluded from the auto-configuration process.

13. What does the @PathVariable annotation do in a Spring Boot REST controller?

Choose one option

a) Maps the URL path to a specific request method
b) Extracts values from the URL path placeholder
c) Links to external web resources
d) Automatically authenticates the request

Answer 13

b) Extracts values from the URL path placeholder

The @PathVariable annotation can be used to extract values from the URI template so that the method can use those values

14. How do you specify active profiles in a Spring Boot application?

Choose one option

a) By editing the maven settings.xml
b) By specifying profiles in application.properties as spring.profiles.active
c) By setting the profile configuration in web.xml
d) Spring Boot does not support active profiles

Answer 14

b) By specifying profiles in application.properties as spring.profiles.active

Active profiles can be specified with the spring.profiles.active property, allowing for environment-specific configurations.

15. Which of the following code snippets demonstrates the correct configuration of Spring Boot Security for securing a REST API?

Choose one option

a) 

@Configuration
@EnableWebSecurity
public class SecurityConfig extends WebSecurityConfigurerAdapter {

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http
            .csrf().disable()
            .authorizeRequests()
                .antMatchers("/api/**").hasRole("ADMIN")
                .anyRequest().permitAll()
                .and()
            .httpBasic();
    }
}


b) 

@SpringBootApplication
@EnableWebSecurity
public class SecurityConfig extends WebSecurityConfigurerAdapter {

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http
            .authorizeRequests()
                .antMatchers("/api/**").authenticated()
                .anyRequest().permitAll()
                .and()
            .httpBasic();
    }
}


c) 

@Configuration
@EnableWebSecurity
public class SecurityConfig extends WebSecurityConfigurerAdapter {

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http
            .authorizeRequests()
                .antMatchers("/api/**").authenticated()
                .anyRequest().permitAll()
                .and()
            .httpBasic()
                .and()
            .csrf().disable();


d) 

@Configuration
@EnableWebSecurity
public class SecurityConfig extends WebSecurityConfigurerAdapter {

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http
            .authorizeRequests()
                .antMatchers("/api/**").permitAll()
                .anyRequest().authenticated()
                .and()
            .httpBasic();
    }
}

Answer 15

Option c) demonstrates the correct configuration of Spring Boot Security for securing a REST API. The code snippet uses the @Configuration annotation to mark the class as a Spring configuration. The @EnableWebSecurity annotation enables Spring Security features. The configure(HttpSecurity http) method is overridden to define the security rules. In this case, /api/** endpoint is restricted to authenticated users only while allowing public access to all other endpoints. The .httpBasic() method configures basic authentication for the REST API.

16. What is the result of the following code snippet?

@Bean
@ConditionalOnProperty(name = "app.feature.enabled", havingValue = "true")
public MyFeature myFeature() {
    return new MyFeature();
}

Choose one option

a) The bean is always created
b) The bean is created only if the property is set to true
c) The bean is not created at all
d) The property must be set to false for the bean to be created

Answer 16

b) The bean is created only if the property is set to true

The @ConditionalOnProperty annotation creates the bean only if the specified property is set to true.

17.  In Spring Boot, what does the spring.jpa.hibernate.ddl-auto property control?

Choose one option

a) The caching mechanism
b) The logging level of Hibernate
c) The automatic schema generation strategy
d) The transaction management settings

Answer 17

c) The automatic schema generation strategy

The spring.jpa.hibernate.ddl-auto property controls how Hibernate handles schema generation, such as create, update, or none.

18. Which of the following statements is true about Spring Database integration?

a) Spring provides a built-in database management system for relational databases
b) Spring only supports integration with SQL Server and Oracle databases
c) Spring provides support for accessing and interacting with databases through JDBC and Object-Relational Mapping (ORM) frameworks
d) Spring Database integration is limited to NoSQL databases only

Answer 18

c) Spring provides support for accessing and interacting with databases through JDBC and Object-Relational Mapping (ORM) frameworks

Spring Framework, along with Spring Boot, offers comprehensive support for database access, including integration with JDBC and various ORM frameworks like Hibernate and JPA. This support extends across a wide range of relational and non-relational databases, facilitating easy configuration, transaction management, and data access within applications. 

 19.  Which of the following is true about Spring Security?

a) Spring Security is a framework that provides authentication and authorization support for Spring-based applications
b) Spring Security is only applicable for securing web applications and does not support other types of applications
c) Spring Security is a stand-alone framework and cannot be integrated with other Spring modules
d) Spring Security does not provide any out-of-the-box support for implementing multi-factor authentication

Answer 19

a) Spring Security is a framework that provides authentication and authorization support for Spring-based applications

It allows developers to easily secure their applications against common security vulnerabilities. It also has support for various authentication mechanisms, such as form-based, HTTP Basic, and OAuth.

20. How can you define a scheduled task in a Spring Boot application?

@Scheduled(fixedRate = 2000)
public void reportCurrentTime() {
    System.out.println("Current time: " + new Date());
}

Choose one option

a) It runs every 2 seconds
b) It is triggered by an event
c) It executes only once
d) It runs at application startup only

Answer 20

a) It runs every 2 seconds

21. Which of the following layers is not part of a typical Spring Boot application?

a) DAO layer
b) Logger layer
c) Service layer
d) Controller layer

Answer 21

b) Logger layer

Common layers in a Spring Boot application include the DAO, Service, and Controller layers; logging is a cross-cutting concern, not a separate layer.

22. What is the default package used in a Spring Boot project if none is specified?

a) main.java
b) default.package
c) org.springframework.boot
d) The root package specified in the @SpringBootApplication class

Answer 22

d) The root package specified in the @SpringBootApplication class

The @SpringBootApplication annotation triggers auto-configuration only within its package and sub-packages, so it acts as the root package if not specified.

23. How can you disable the default web server in a Spring Boot application in build process?

a) Set server.enabled: false in application.properties
b) Set server.port: 0 in application.properties
c) Use the @DisableWebServer annotation
d) Use a command-line argument to set the server port to 0

Answer 23

b) Set server.port: 0 in application.properties

Setting the server port to 0 effectively disables the embedded web server.

24. How can you switch from using the default Tomcat server to Jetty in a Spring Boot application?

a) Modify server.xml
b) Change the server property in application.properties
c) Exclude Tomcat and include Jetty dependencies in pom.xml
d) Use @EnableJetty annotation

Answer 24

c) Exclude Tomcat and include Jetty dependencies in pom.xml

Tomcat is included by default, so you must exclude it and add Jetty’s dependencies to switch the server.

25. What is Actuator in Spring Boot?

a) A tool to monitor and manage applications
b) A GUI design tool
c) A security framework
d) A configuration tool

Answer 25

a) A tool to monitor and manage applications

Spring Boot Actuator provides various endpoints for monitoring and managing the application, such as health checks and metrics.

We would love to hear from you! Please leave your comments and share your scores in the section below

vibssingh

Performance Testing – Multiple Choice Questions and Answers – MCQ1

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Welcome to the Performance Testing Quiz! This blog post features 25 multiple-choice questions that explore basic concepts of Performance Testing.

1. What is the primary goal of performance testing?

a) To identify issues in navigation flow
b) To ensure that an application performs well under expected load
c) To validate user interface design
d) To test security vulnerabilities

Answer 1

b) To ensure that an application performs well under expected load

Performance testing evaluates how an application behaves under expected or stress conditions to ensure it meets performance criteria.

2. Which tool is commonly used for Performance Testing?

a) Selenium
b) Apache JMeter
c) Visual Studio Code
d) Postman

Answer 2

b) Apache JMeter

Apache JMeter is a popular open-source tool for performing load and performance testing.

3. What is Throughput in Performance Testing?

Choose one option

a) Number of lines of code executed
b) Response time of the system
c) Number of transactions processed in a given timeframe
d) Number of errors per second

Answer 3

c) Number of transactions processed in a given timeframe

Throughput measures the number of transactions or requests processed in a given period.

4. What type of performance testing aims to find out how a system operates under heavy loads?

Choose one option

a) Load Testing
b) Stress Testing
c) Soak Testing
d) Security Testing

Answer 4

c) Stress Testing

Stress testing determines how a system performs under peak or extreme conditions, beyond normal operational capacity.

5. What is the main objective of load testing?

a) To break the system
b) To evaluate software scalability
c) To test the system’s reaction under varying traffic loads
d) To check system breaches

Answer 5

c) To test the system’s reaction under varying traffic loads

Load testing evaluates how a software application behaves when it is subjected to varying loads, usually simulating multiple users.

6. Performance Testing is a type of

Choose one option

a) Functional Testing
b) Non-Functional Testing
c) Security Testing
d) None of the above

Answer 6

b) Non-Functional Testing

7. Performance is concerned with achieving ………………… that meet the performance objectives for the project or product

Choose one option

a) Response times, Throughput, and Stress levels
b) Response times, Throughput, and Resource-utilization levels
c) Reason times, Throughput, and Resource-utilization levels
d) Response times, Click-through, and Resource-utilization levels

Answer 7

b) Response times, Throughput, and Resource-utilization levels

8. What is Spike Testing in Performance Testing?

Choose one option

a) Sudden large increases in system load
b) Gradually increasing system load
c) Reducing system performance
d) Testing system updates

Answer 8

a) Sudden large increases in system load

Spike testing measures how a system reacts to sudden and significant increases in load.

9. What is endurance testing?

a) Testing the system’s ability to handle high traffic during peak hours
b) Testing the system’s compatibility with different operating systems
c) Testing the system’s performance under normal conditions
d) Testing the system’s ability to handle an increasing load over an extended period

Answer 9

d) Testing the system’s ability to handle an increasing load over an extended period

Endurance testing involves testing a system over a prolonged period to determine its ability to perform under sustained load without performance degradation.

10. What is the purpose of a baseline test in performance testing?

a) To test under maximum load
b) To establish a benchmark for future tests
c) To identify security issues
d) To simulate network failures

Answer 10

b) To establish a benchmark for future tests

11. What is transaction response time?

Choose one option

a) Time to write transaction
b) Time to complete entire business transaction
c) Time to start transaction
d) Time to log transaction

Answer 11

b) Time to complete entire business transaction

12.  Which of the following is NOT a goal of performance testing?

Choose one option

a) Detecting memory leakage
b) Determining system sustainability
c) Evaluating error handling
d) Reducing hardware requirements

Answer 12

d) Reducing hardware requirements

13. What does KPI stand for in the context of performance testing?

Choose one option

a) Key Performance Indicator
b) Knowledge Program Initiative
c) Key Process Integration
d) Kernel Performance Index

Answer 13

a) Key Performance Indicator

14. When should performance testing be conducted?

Choose one option

a) Only after code changes
b) Regularly throughout the development lifecycle
c) After production deployment
d) Only during the initial phases of development

Answer 14

b) Regularly throughout the development lifecycle

15. Which of the following can impact performance testing results?

Choose one option

a) Developer skill levels
b) Network capacity and configuration
c) HR policies
d) Office location

Answer 15

b) Network capacity and configuration

16. What does ‘Think Time’ refer to in Load Testing?

Choose one option

a) The delay between user actions
b) Time required for machine learning predictions
c) AI decision-making time
d) Load balancing wait time

Answer 16

a) The delay between user actions

17.  What is the primary concern of resource utilization testing?

Choose one option

a) Adequate electricity supply
b) Efficient use of time during testing
c) The impact of an application on system resources
d) Cost of the software tools

Answer 17

c) The impact of an application on system resources

18. What does ‘concurrency’ refer to in performance testing?

a) Parallel software development processes
b) Simultaneous execution of multiple tasks
c) Single user testing multiple features
d) Continuous testing cycles

Answer 18

b) Simultaneous execution of multiple tasks

 19.  Which of the following is true about cloud performance testing?

a) It is more cost-effective than traditional methods
b) It cannot simulate real-world traffic
c) It requires dedicated on-premise hardware
d) It doesn’t support network latency measurements

Answer 19

a) It is more cost-effective than traditional methods

20. Which metric is used to measure the speed at which a system returns to a steady state after a particular load?

Choose one option

a) Response time
b) Throughput
c) Recovery time
d) Load time

Answer 20

c) Recovery time

21. Which factors impact system performance during Performance Testing?

Choose one option

a) Only font sizes and text placement
b) Browser color schemes and UI themes
c) User location and screen resolution
d) CPU, Memory, Database, Network latency

Answer 21

d) CPU, Memory, Database, Network latency

22. Which of the following is not a type of performance test?

Choose one option

a) Endurance testing
b) Load testing
c) Compatibility testing
d) Stress testing

Answer 22

c) Compatibility testing

23. Performance Testing environment should be scaled at least up to 50% of the production environment?

Choose one option

a) Yes
b) No

Answer 23

a) Yes

24. Which metric is NOT typically measured in performance testing?

a) Response time
b) Throughput
c) Code coverage
d) Resource utilization

Answer 24

c) Code coverage  

25. What is steady state in performance testing?

a) System startup phase
b) Period of constant load
c) System shutdown phase
d) Error state

Answer 25

b) Period of constant load

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Java – Multiple Choice Questions and Answers – Arrays

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Welcome to the Java Quiz! This blog post features 25 multiple-choice questions that explore the concepts of Arrays in Java.

1. What is an array in Java?

a) A data structure that can hold elements of different types
b) A class that allows storing single data type elements in a contiguous memory location
c) A collection of elements in no specific order
d) A method for sorting elements

Answer 1

b) A class that allows storing single data type elements in a contiguous memory location

Arrays in Java are used to store multiple values of the same data type in a contiguous memory location.

2. How do you instantiate an array of integers with 10 elements in Java?

a) int[] arr = new int[10];
b) int arr = new int(10);
c) int arr[10] = new int[];
d) int(10) arr = new int[];

Answer 2

a) int[] arr = new int[10];

3. What is the default value of an element in an int array in Java?

Choose one option

a) 1
b) 0
c) null
d) Undefined

Answer 3

b) 0

In Java, arrays of primitive types like int are initialized to their default values. The default value for int is 0

4. What will be the output of the following Java program?

class array_output 
    {
        public static void main(String args[]) 
        {
            int array_variable [] = new int[10];
	        for (int i = 0; i < 10; ++i) 
            {
                array_variable[i] = i;
                System.out.print(array_variable[i] + " ");
                i++;
            }
        } 
   }

Choose one option

a) 0 2 4 6 8
b) 1 3 5 7 9
c) 0 1 2 3 4 5 6 7 8 9
d) 1 2 3 4 5 6 7 8 9 10

Answer 4

a) 0 2 4 6 8

When an array is declared using new operator then all of its elements are initialized to 0 automatically. for loop body is executed 5 times as whenever controls comes in the loop i value is incremented twice, first by i++ in body of loop then by ++i in increment condition of for loop.

5. What is the maximum number of dimensions an array can have in Java?

a) 1
b) 255
c) 2
d) No theoretical limit

Answer 5

b) 255 

Java allows arrays to have up to 255 dimensions.

6. What will be the output of the following Java program?

public class array_output {

    public static void main(String args[])
    {
        char array_variable [] = new char[10];
        for (int i = 0; i < 10; ++i)
        {
            array_variable[i] = 'i';
            System.out.print(array_variable[i] + "");
        }
    }
}

Choose one option

a) 1 2 3 4 5 6 7 8 9 10
b) 0 1 2 3 4 5 6 7 8 9 10
c) i j k l m n o p q r
d) i i i i i i i i i i

Answer 6

d) i i i i i i i i i i

When an array is declared using the new operator, all of its elements are automatically initialized to default values—0 for numeric types, null for reference types, and ‘\0’ (null character) for char.

7. What will be the output of the following Java program?

public class array_output {
    public static void main(String args[])
    {
        double num[] = {5.5, 10.1, 11, 12.8, 56.9, 2.5};
        double result;
        result = 0;
        for (int i = 0; i < 6; ++i)
            result = result + num[i];
            System.out.print(result/6);

    }
}

Choose one option

a) 16.34
b) 16.566666644
c) 16.46666666666667
d) 16.46666666666666

Answer 7

c) 16.46666666666667

8. What happens if you try to access an index of an array that is out of bounds?

Choose one option

a) Compile-time error
b) Returns null
c) Throws ArrayIndexOutOfBoundsException
d) None of the above

Answer 8

c) Throws ArrayIndexOutOfBoundsException

9. How do you declare an array of strings?

a) String[] arr;
b) String arr[];
c) String arr();
d) String arr{};

Answer 9

a) String[] arr;

This is the standard way of declaring an array of strings in Java.

10. Which of the following is a valid declaration and initialization of String array in Java

a) String[] names ={“Tim”,”Mark”,”Charlie”}
b) String names[] ={“Tim”,”Mark”,”Charlie”}
c) String[3] names ={“Tim”,”Mark”,”Charlie”}
d) Both a) and b)
e) Both a) and c)

Answer 10

d) Both a) and b)

String[3] names = {“Tim”, “Mark”, “Charlie”};` is incorrect because Java does not allow specifying the size of the array within square brackets during initialization in this manner.

11. What will be the output?

public class Test {
    public static void main(String[] args) {
        String[] arr = {"Java", "Python", "C++"};
       System.out.println(arr[1]);
    }
}

Choose one option

a) Java
b) Python
c) C++
d) Compilation error

Answer 11

b) Python

arr[1] accesses the second element of the array, which is “Python”.

12.  Which of the following statements is true?

Choose one option

a) Arrays are immutable
b) Arrays are objects
c) Arrays store elements of any data type
d) Arrays automatically grow

Answer 12

b) Arrays are objects

In Java, arrays are objects and are part of the java.lang package.

13. What is the primary use of the `System.arraycopy()` method in Java?

Choose one option

a) To copy one array to another
b) To reverse an array
c) To sort an array
d) To find an element in an array

Answer 13

a) To copy one array to another

System.arraycopy() is used to copy elements from one array to another.

14. What is printed by the following code snippet?

public class Test {
    public static void main(String[] args) {
       int[] arr = new int[5];
      System.out.println(arr[1]);
    }
}

Choose one option

a) 0
b) null
c) undefined
d) Compilation error

Answer 14

a) 0

Integer arrays are initialized to 0 by default.

15. What will be the result of this program?

public class array_output {
    public static void main(String args[])
    {
        int[] arr = {1, 2, 3, 4};
        System.out.println(arr.length);
    }
}

Choose one option

a) 0
b) 3
c) 4
d) Compilation error

Answer 15

c) 4

arr.length returns the number of elements in the array, which is 4.

16.  What exception is thrown by Java code when trying to store values in a sufficiently large dimension of an array but with the wrong data type?

Choose one option

a) ArrayIndexOutOfBoundsException
b) IllegalArgumentException
c) ClassCastException
d) ArrayStoreException

Answer 16

d) ArrayStoreException

ArrayStoreException occurs when attempting to store incorrect types into arrays of object types.

17.  Which of the following is not a valid way to declare a two-dimensional array in Java?

Choose one option

a) int[][] arr = new int[3][3];
b) int arr[][] = new int[3][3];
c) int[] arr = new int[3][];
d) int[][] arr = new int[][];

Answer 17

d) int[][] arr = new int[][];

Option D is invalid because while it declares a two-dimensional array, it does not specify the size of either dimension at the time of declaration.

18. What is the correct way to iterate over a Java array using an enhanced for loop?

a) for (int i : arr)
b) for (int i = 0; i < arr.length; i++)
c) for (arr : int i)
d) for (arr i : int)

Answer 18

a) for (int i : arr)

The enhanced for loop in Java is written as for (type variable : array).

 19.  What will happen if you try to store a double value into an int array?

a) The value will be rounded
b) The value will be truncated
c) A ClassCastException will be thrown
d) A compile-time error

Answer 19

d) A compile-time error

You cannot store a double value in an int array without explicit casting, leading to a compile-time error.

20. What is the output of the following code?

public class array_output {
    public static void main(String args[])
    {
        int[] arr = {2, 4, 6, 8};
        System.out.println(arr[arr.length]);
    }
}

Choose one option

a) 8
b) 4
c) 0
d) ArrayIndexOutOfBoundsException

Answer 20

d) ArrayIndexOutOfBoundsException

Since array indices are 0-based, accessing arr[arr.length] is out of bounds. The valid indices for this array are from 0 to arr.length – 1.

21. What is the output of the following code?

public class array_output {
    public static void main(String args[]) {
        int[] arr = {1, 2, 3, 4, 5};
        for (int i = 0; i < arr.length; i++) {
            arr[i] = arr[i] * 2;
        }
        System.out.println(arr[2]);
    }
}

Choose one option

a) 3
b) 6
c) 8
d) 10

Answer 21

b) 6

The loop multiplies each element by 2. Therefore, arr[2] becomes 3 * 2 = 6.

22. What will be the output of the below program?

public class array_output {
    
    public static void main(String args[]) {
        int[] arr = {10, 20, 30, 40};
        System.out.println(arr[1] + arr[2]);
    }
}

Choose one option

a) 30
b) 50
c) 60
d) 70

Answer 22

b) 50

arr[1] is 20 and arr[2] is 30, so the sum is 20 + 30 = 50.

23. Can you resize an array in Java after it is created?

Choose one option

a) Yes
b) No

Answer 23

b) No

24. How can you access the element at the second row and third column of a two-dimensional array “matrix”?

a) matrix[3][2]
b) matrix[2, 3]
c) matrix[1][2]
d) matrix[2:3]

Answer 24

c) matrix[1][2]

Array indexing starts at 0 in Java, so the second row is index 1, and the third column is index 2.   

25. What will be the default value of the elements in a two-dimensional array of type `int[][]` in Java?

a) null
b) 0
c) undefined
d) Compilation error

Answer 25

b) 0

For arrays of primitive data types like int, the default value of the elements is 0.

We would love to hear from you! Please leave your comments and share your scores in the section below

vibssingh

ETL Testing – Multiple Choice Questions and Answers – MCQ2

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Welcome to the ETL Testing Quiz! This blog post features 25 multiple-choice questions that explore the concepts of ETL Testing.

1.  Using an ____ tool, data is extracted from multiple data sources, transformed, and loaded into a data warehouse after joining fields, calculating, and removing incorrect data fields.

a) ETL
b) TEL
c) LET
d) LTE

Answer 1

a) ETL

2. Which phase of ETL testing involves comparing source data with target data?

a) Production Validation Testing
b) Source to Target Count Testing
c) Source to Target Data Testing
d) Metadata Testing

Answer 2

c) Source to Target Data Testing

Source to Target Data Testing involves comparing the data in the source system with the data in the target system to ensure that all data has been correctly extracted, transformed, and loaded without any loss or corruption.

3. What is Data Profiling in ETL testing?

Choose one option

a) Creating user profiles for data access
b) Analyzing source data to understand its content, structure, and quality
c) Profiling the performance of ETL jobs
d) Creating profiles of data warehouse users

Answer 3

b) Analyzing source data to understand its content, structure, and quality

This helps in identifying potential issues early in the ETL process and aids in designing appropriate transformation rules.

4. A performance test is conducted to determine if ETL systems can handle ____ at the same time.

Choose one option

a) Multiple Users
b) Transactions
c) Both a) and b)
d) None of the above

Answer 4

c) Both a) and b)

A performance test is conducted to determine if ETL systems can handle multiple users and transactions at the same time.

.

5. Which type of testing checks that all data from the source system is loaded into the target system without any missing records?

a) Performance Testing
b) Data Completeness Testing
c) Security Testing
d) Usability Testing

Answer 5

b) Data Completeness Testing

Data Completeness Testing verifies that all expected data is loaded from source systems to destination systems without any omissions.

6. Why is data profiling important in ETL testing?

Choose one option

a) It formats the output reports
b) It identifies issues in data quality before loading
c) It integrates with third-party tools
d) It enhances user interface

Answer 6

b) It identifies issues in data quality before loading

 Data profiling helps in understanding data structures, quality, and ensuring data accuracy and consistency before loading.

7. In ETL, what is a common method for handling inconsistent data?

Choose one option

a) Data Archiving
b) Data Cleansing
c) Data Encryption
d) Data Mapping

Answer 7

b) Data Cleansing

Data cleansing involves procedures to correct or remove inaccurate, incomplete, and duplicate data to ensure data quality and consistency.

8. Before data is moved to the warehouse, the extracted data can be validated in the ____ area.

Choose one option

a) Staging
b) Staggering
c) Studying
d) None

Answer 8

a) Staging

Before data is moved to the warehouse, the extracted data can be validated in the staging area.

9. Which of the following is/are the method(s) to extract the data?

a) FULL Extraction
b) Partial Extraction – Without Update Notification
c) Partial Extraction – With Update Notification
d) All of the above

Answer 9

d) All of the above

10. Which of the following is/are the validation(s) using the extraction(s)?

a) Check the source data against the record
b) Ensure that the data type is correct
c) There will be a check to see if all the keys are there
d) All of the above

Answer 10

d) All of the above

11. Which of the following is/are the type(s) of loading?

Choose one option

a) Initial Load
b) Incremental Load
c) Full Refresh
d) All of the above

Answer 11

d) All of the above

12.  With a ____, all tables are erased and reloaded with new information.

Choose one option

a) Full Load
b) Incremental Load
c) Full Refresh
d) All of the above

Answer 12

c) Full Refresh

With a Full Refresh, all tables are erased and reloaded with new information.

13. The term is ETL now extended to ____ or Extract, Monitor, Profile, Analyze, Cleanse, Transform, and Load.

Choose one option

a) E-MPAC-TL
b) E-PAC-TL
c) E-MAP-TL
d) E-MPAA-TL

Answer 13

a) E-MPAC-TL

The term is now extended to E-MPAC-TL or Extract, Monitor, Profile, Analyze, Cleanse, Transform, and Load.

14. In ____, analysis and validation of the data pattern and formats will be performed, as well as identification and validation of redundant data across data sources to determine the actual content, structure, and quality of the data.

Choose one option

a) Data Profiling
b) Data Analysis
c) Source Analysis
d) Cleansing

Answer 14

a) Data Profiling

In data profiling, analysis and validation of the data pattern and formats will be performed, as well as identification and validation of redundant data across data sources to determine the actual content, structure, and quality of the data.

15. ETL testing is also known as –

Choose one option

a) Table balancing
b) Product Reconciliation
c) Both a) and b)
d) None of the above

Answer 15

c) Both a) and b)

ETL testing is sometimes referred to as table balancing and product reconciliation as it involves ensuring that the data transferred from the source to the destination is accurate and consistent, essentially “balancing” or reconciling between systems.

16. Which tool is not typically used for ETL Testing?

Choose one option

a) Informatica
b) Apache JMeter
c) Oracle Data Integrator
d) Microsoft SSIS

Answer 16

b) Apache JMeter

JMeter is primarily used for performance testing, not specifically for ETL testing, which deals with data processes and transformations.

17.  What does NULL value testing check for in ETL?

Choose one option

a) The presence of empty strings
b) The correct handling of NULL values during transformation
c) The speed of processing NULL values
d) The number of NULL values in the source data

Answer 17

b) The correct handling of NULL values during transformation

NULL value testing in ETL checks for the correct handling of NULL values during the transformation process. It ensures that NULL values are properly recognized, transformed, and loaded into the target system according to the defined business rules.

18. What is the purpose of Incremental ETL Testing?

a)  To test only new or updated data since the last ETL run
b) To gradually increase the volume of test data
c) To test the ETL process in small increments
d) To incrementally improve the ETL process

Answer 18

a)  To test only new or updated data since the last ETL run

Incremental ETL Testing is performed to test only the new or updated data since the last ETL run. This type of testing is crucial for ensuring that ongoing data updates are correctly processed and integrated into the target system without affecting existing data.

 19.  What is the main purpose of Performance Testing in ETL?

a) To test the user interface performance
b) To measure and optimize the speed and efficiency of ETL processes
c) To check the performance of database queries
d) To test the network performance

Answer 19

b) To measure and optimize the speed and efficiency of ETL processes

20. You are testing the ETL process for a financial institution that deals with sensitive customer data. What security measures should you consider during ETL testing to ensure data protection?

Choose one option

a) Implementing data encryption during extraction
b) Disabling firewalls to facilitate data flow
c)  Using publicly accessible APIs for data transfer
d) Storing sensitive data in plain text format

Answer 20

a) Implementing data encryption during extraction

 Implementing data encryption during extraction ensures the protection of sensitive data. This protection occurs while transferring data from source to target. It mitigates the risk of unauthorized access.

21. During ETL testing, you notice that duplicate records are being loaded into the target database. What ETL test scenario could help identify and prevent such occurrences?

Choose one option

a) Testing data transformations with small datasets
b) Testing with production-sized datasets
c) Testing data quality constraints
d) Testing data load performance

Answer 21

C) Testing data quality constraints

Testing data quality constraints, such as uniqueness constraints, can help identify and prevent the loading of duplicate records into the target database.

22. While testing the ETL process, you encounter a situation where the source system undergoes a schema change. How should you approach this situation in terms of ETL testing?

Choose one option

a) Ignore the schema change and proceed with testing
b) Pause testing until the schema change is reverted
c) Modify ETL mappings to accommodate the new schema
d) Notify the stakeholders and discontinue testing

Answer 22

c) Modify ETL mappings to accommodate the new schema

23. You are conducting ETL testing on a procedure that involves transferring data from a flat file into a database. However, the data loading stage is slower than anticipated, and the system resources are not being fully utilized. What measures could you take to enhance the performance of the data loading process?

Choose one option

a)  Increase database server capacity
b) Optimize SQL queries
c) Increase the file size for faster loading
d) Disable data validation during loading

Answer 23

b) Optimize SQL queries

 Optimizing SQL queries can significantly improve data loading performance by reducing query execution time. This can lead to better resource utilization and faster ETL processing.

24. While conducting ETL testing, you face a scenario where the source system has intermittent outages. How can you maintain data integrity and consistency despite these outages?

a) Pause the ETL process until the source system is stable
b) Implement retry mechanisms for data extraction
c) Skip the affected data during extraction
d) Disable error handling temporarily

Answer 24

b) Implement retry mechanisms for data extraction

Implementing retry mechanisms for data extraction helps ensure that data is eventually extracted successfully, even if the source system experiences intermittent outages. This helps maintain data integrity and consistency.  

25. What distinguishes a dimensional data model used in ETL processes?

a) High normalization levels
b) Use of rows and columns
c) Use of fact and dimension tables
d) Complex security features

Answer 25

c) Use of fact and dimension tables

Dimensional models use fact and dimension tables to organize and represent data for analytical purposes effectively.

We would love to hear from you! Please leave your comments and share your scores in the section below

vibssingh

ETL Testing – Multiple Choice Questions and Answers – MCQ1

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Welcome to the ETL Testing Quiz! This blog post features 25 multiple-choice questions that explore basic concepts of ETL Testing.

1. What is the full form of ETL?

a) Extract, Transformation and Load
b) Extract, Transformation and Lead
c) Extract, Transfusion and Load
d) Extract, Transfusion and Lead

Answer 1

a) Extract, Transformation and Load

2. To fetch data from one database and place it in another, ETL combines all ____ database functions into one tool.

a) One
b) Two
c) Three
d) Four

Answer 2

c) Three

To fetch data from one database and place it in another, ETL combines all three database functions into one tool.

3. What is the main purpose of ETL Testing?

Choose one option

a) To test application UI
b) To ensure data is extracted, transformed, and loaded correctly
c) To verify API endpoints
d) To check database installation

Answer 3

b) To ensure data is extracted, transformed, and loaded correctly

4. Which of the following is NOT an ETL tool?

Choose one option

a) Informatica
b) Talend
c) QlikView
d) DataStage

Answer 4

c) QlikView

QlikView is a reporting/visualization tool, not an ETL tool.

5. Data in ETL testing is usually extracted from

a) Flat files
b) Databases
c) APIs
d) All of the above

Answer 5

d) All of the above

6. In ETL testing, surrogate keys are

Choose one option

a) Natural business keys
b) System-generated unique identifiers
c) Duplicate keys
d) Encrypted passwords

Answer 6

b) System-generated unique identifiers

7. Getting information from a database is called ___

Choose one option

a) Extracting
b) Transforming
c) Loading
d) None

Answer 7

a) Extracting

8. The process of ____ data involves converting it from one form to another.

Choose one option

a) Extracting
b) Transforming
c) Loading
d) None

Answer 8

b) Transforming

9. Writing data into a database is called ___

a) Extracting
b) Transforming
c) Loading
d) None

Answer 9

c) Loading

10. ETL is often used to build a –

a) Data Center
b) Data Warehouse
c) Data Care Center
d) Data Set

Answer 10

b) Data Warehouse

11. In today’s environment, ETL is becoming more and more necessary for many reasons, including:

Choose one option

a) In order to make critical business decisions, companies use ETL to analyze their business data.
b) Data warehouses are repositories where data is shared.
c) In ETL, data is moved from a variety of sources into a data warehouse.
d) All of the above

Answer 11

d) All of the above

12.  What is the main challenge in ETL Testing?

Choose one option

a) Verifying UI elements
b) Handling large volumes of data
c) Testing mobile devices
d) Validating screen layouts

Answer 12

b) Handling large volumes of data

13. Which is a popular open-source ETL tool?

Choose one option

a) Informatica
b) Talend
c) DataStage
d) Ab Initio

Answer 13

b) Talend

14. In ETL testing, reconciliation reports are used for

Choose one option

a) Matching UI data
b) Comparing source and target data counts
c) API validation
d) Security audit

Answer 14

b) Comparing source and target data counts

15. What is Incremental Load in ETL?

Choose one option

a) Loading full data every time
b) Loading only new/changed records
c) Reloading only primary keys
d) Reloading metadata only

Answer 15

b) Loading only new/changed records

16. What does CDC stand for in ETL?

Choose one option

a) Change Data Capture
b) Central Data Collection
c) Clean Data Conversion
d) Core Data Copy

Answer 16

a) Change Data Capture

17.  Which SQL command is used to modify existing data in a table?

Choose one option

a) Alter
b) Update
c) Modify
d) Change

Answer 17

b) Update

The UPDATE statement is used to modify existing data in a table based on specified conditions.

18. You are testing an ETL process that extracts customer data from a source system and loads it into a data warehouse. During testing, you notice that some customer records have not been properly transformed, resulting in missing information. What could be the potential causes of this issue?

a)  Inaccurate data mapping
b) Transformation logic errors
c) Data type mismatches
d) Insufficient data profiling

Answer 18

a)  Inaccurate data mapping

 19.  While testing an ETL process, you encounter duplicate records in the target database. What strategies can you employ to identify and eliminate these duplicates?

a) Implement deduplication logic in the transformation phase
b) Utilize SQL queries with DISTINCT keyword
c) Perform data profiling to identify duplicate patterns
d) Leverage hashing algorithms for record comparison

Answer 19

a) Implement deduplication logic in the transformation phase and c) Perform data profiling to identify duplicate patterns

20. During ETL testing, you encounter data quality issues, such as missing values and inconsistencies. How can you ensure data quality is maintained throughout the ETL process?

Choose one option

a) Implement data validation checks at each stage
b) Use data profiling to identify anomalies
c)  Perform data cleansing before transformation
d) Employ referential integrity constraints

Answer 20

a) Implement data validation checks at each stage

21. Which is NOT a challenge in ETL testing?

Choose one option

a) Large volume of data
b) Data quality issues
c) Testing across multiple systems
d) GUI responsiveness

Answer 21

d) GUI responsiveness

22. Which of the following checks record counts between source and target?

Choose one option

a) Data Completeness Testing
b) Data Transformation Testing
c) Regression Testing
d) Negative Testing

Answer 22

a) Data Completeness Testing

23. Data transformation in ETL testing may include

Choose one option

a) Aggregations
b) Data type conversions
c) Business rule application
d) All of the above

Answer 23

d) All of the above

24. A star schema consists of

a) Fact table and dimension tables
b) Only fact tables
c) Only dimension tables
d) Normalized tables

Answer 24

a) Fact table and dimension tables  

25. In ETL testing, ‘mapping document’ is used to

a) Define schema design
b) Describe transformation rules
c) Maintain test cases
d) Automate test execution

Answer 25

b) Describe transformation rules

We would love to hear from you! Please leave your comments and share your scores in the section below

vibssingh

Java – Multiple Choice Questions and Answers – Strings

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Welcome to the Java Quiz! This blog post features 25 multiple-choice questions that explore the concepts of Strings in Java.

1. What is the primary characteristic of strings in Java?

a) Mutable
b) Immutable
c) Dynamic
d) External

Answer 1

b) Immutable

Strings in Java are immutable, meaning their values cannot be changed once created.

2. What is the correct way to declare a String in Java?

a) String str = ‘Hello’;
b) String str = new String(“Hello”);
c) String str = String(“Hello”);
d) String str = Hello;

Answer 2

b) String str = new String(“Hello”);

Strings in Java are declared using String str = new String(“Hello”); or simply String str = “Hello”;.

3. What is the default value of an element in an int array in Java?

Choose one option

a) 1
b) 0
c) null
d) Undefined

Answer 3

b) 0

In Java, arrays of primitive types like int are initialized to their default values. The default value for int is 0

4. What will be the output of the following Java program?

class Test
    {
        public static void main(String args[]) 
        {
            int array_variable [] = new int[10];
	        for (int i = 0; i < 10; ++i) 
            {
                array_variable[i] = i;
                System.out.print(array_variable[i] + " ");
                i++;
            }
        } 
   }

Choose one option

a) 0 2 4 6 8
b) 1 3 5 7 9
c) 0 1 2 3 4 5 6 7 8 9
d) 1 2 3 4 5 6 7 8 9 10

Answer 4

a) 0 2 4 6 8

When an array is declared using new operator then all of its elements are initialized to 0 automatically. for loop body is executed 5 times as whenever controls comes in the loop i value is incremented twice, first by i++ in body of loop then by ++i in increment condition of for loop.

5. Why are Strings immutable in Java?

a) To improve performance
b) To allow modifications in-place
c) To ensure thread safety and security
d) Because Java does not support mutable objects

Answer 5

c) To ensure thread safety and security

String immutability ensures that once created, a String cannot be modified, making it thread-safe and secure.

6. What will be the output of the following Java program?

public class Test {
    
    public static void main(String args[]) {
        String obj = "I" + "like" + "Java";
        System.out.println(obj);
    }
}

Choose one option

a) I
b) like
c) Java
d) IlikeJava

Answer 6

d) IlikeJava

 Java defines an operator +, it is used to concatenate strings.

7. What will be the output of the following Java program?

public class Test {
    
    public static void main(String args[]) {
        String obj = "I LIKE JAVA";
        System.out.println(obj.charAt(3));
    }
}

Choose one option

a) I
b) L
c) K
d) E

Answer 7

a) I

charAt() is a method of class String which gives the character specified by the index. obj.charAt(3) gives 4th character

8. What will be the output of the following Java program?

public class Test {

    public static void main(String args[]) {
        String obj = "I LIKE JAVA";
        System.out.println(obj.length());
    }
}

Choose one option

a) 9
b) 10
c) 11
d) 12

Answer 8

c) 11

The string “I LIKE JAVA” contains 11 characters, including the spaces. The length() method returns the total number of characters in the string. So, the output is 11.

9. What will be the output of the following Java program?

public class Test {

    public static void main(String args[]) {
        String obj = "hello";
        String obj1 = "world";
        String obj2 = obj;
        obj2 = " world";
        System.out.println(obj + " " + obj2);
    }
}

a) hello hello
b) world world
c) hello world
d) world hello

Answer 9

c) hello world

This is the standard way of declaring an array of strings in Java.

10. Which of the following is a valid declaration and initialization of String array in Java

public class Test {

    public static void main(String args[]) {
        String obj = "hello";
        String obj1 = "world";
        String obj2 = "hello";
        System.out.println(obj.equals(obj1) + " " + obj.equals(obj2));
    }
}

a) false false
b) true true
b) true false
d) false true

Answer 10

d) false true

equals() is method of class String, it is used to check equality of two String objects, if they are equal, true is retuned else false.

11. What will be the output?

public class Test {

    public static void main(String args[]) {
        System.out.println("Hello World".indexOf('W'));
    }
}

Choose one option

a) 0
b) 5
c) 6
d) -1

Answer 11

c) 6

The indexOf() method returns the index of the first occurrence of the specified character.

12.   How do you compare two strings in Java?

Choose one option

a) ==
b) equals()
c) compareTo()
d) Both b) and c)

Answer 12

d) Both b) and c)

Use equals() for value comparison and compareTo() for lexicographical order.

13. Which of the following will return a substring from a string?

Choose one option

a) str.sub()
b) str.substring()
c) str.slice()
d) str.split()

Answer 13

b) str.substring()

The substring() method extracts a substring from the string.

14. What is printed by the following code snippet?

public class Test {

    public static void main(String args[]) {
        System.out.println("Java".compareTo("Java"));
    }
}

Choose one option

a) 0
b) 1
c) -1
d) Compilation error

Answer 14

a) 0

The compareTo() method returns 0 if the two strings are equal.

15. What will be the result of this expression?

public class Test {

    public static void main(String args[]) {
        System.out.println("abc".substring(1, 3));
    }
}

Choose one option

a) ab
b) abc
c) bc
d) a

Answer 15

c) bc

The substring(start, end) method returns the substring from start index to end-1.

16.  How can you check if a string is empty?

Choose one option

a) str.isEmpty()
b) str.length() == 0
c) Both a) and b)
d) str.equals(“”)

Answer 16

c) Both a) and b)

Both methods can be used to check if a string is empty.

17.  What does the StringBuilder class do?

Choose one option

a) It creates immutable strings.
b) It creates mutable strings.
c) It converts strings to numbers.
d) It is not a class in Java.

Answer 17

b) It creates mutable strings.

StringBuilder allows for the creation of mutable strings, which can be modified.

18. Which method would you use to split a string into an array based on a delimiter?

a) split()
b) divide()
c) slice()
d) substring()

Answer 18

a) split()

The split() method splits a string into an array based on a specified delimiter.

 19.  Which of the following will convert a string to a number?

a) parseInt()
b) valueOf()
c) toNumber()
d) Both a) and b)

Answer 19

d) Both a) and b)

Both parseInt() and valueOf() can convert a string to a number.

20. What is the output of the following code?

public class Test {

    public static void main(String args[]) {
        System.out.println("abc".repeat(3));
    }
}

Choose one option

a) abcabcabc
b) abc abc abc
c) abcabc abc
d) Compilation Error

Answer 20

a) abcabcabc

The repeat(int) method returns a string whose value is the concatenation of the specified string repeated the given number of times.

21. What is the output of the following code?

public class Test {

    public static void main(String args[]) {
        System.out.println("Hello".replace('e', 'a'));
    }
}

Choose one option

a) Hallo
b) Hello
c) Halla
d) Hella

Answer 21

a) Hallo

The replace() method replaces the specified character with another character.

22. What will be the output of the following program

public class Test {

    public static void main(String args[]) {
        String s1 = new String("Hello");
        String s2 = new String("Hello");
        System.out.println(s1 == s2);
    }
}

Choose one option

a) true
b) false
c) Compilation error
d) Runtime error

Answer 22

b) false

The == operator compares object references, not values. Since s1 and s2 are two different objects, it returns false.

23. Which of these methods can be used to check if two strings are equal, ignoring case considerations?

Choose one option

a) equals()
b) equalsIgnoreCase()
c) compareTo()
d) compareIgnoreCase()

Answer 23

b) equalsIgnoreCase()

The equalsIgnoreCase() method compares two strings, ignoring case differences.

24. What will be the result if you try to modify an existing string?

a) The string will be changed
b) A new string will be created
c) An exception will be thrown
d) Compilation error

Answer 24

b) A new string will be created

Strings in Java are immutable, so any modification creates a new string. 

25. Which method checks if a string starts with a specified prefix?

a) beginsWith()
b) start()
c) startsWith()
d) prefix()

Answer 25

c) startsWith()

The startsWith() method checks if the string begins with the specified prefix.

We would love to hear from you! Please leave your comments and share your scores in the section below

vibssingh

Java – Multiple Choice Questions and Answers – Inheritance & Polymorphism

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Welcome to the Java Quiz! This blog post features 25 multiple-choice questions that explore the concepts of Inheritance & Polymorphism in Java.

1. What is inheritance in Java?

a) A mechanism where one class acquires the properties of another
b) A way to allow multiple classes to have the same method names
c) A class that implements an interface
d) None of the above

Answer 1

a) A mechanism where one class acquires the properties of another 

2. Which keyword is used for inheritance in Java?

a) implements
b) extends
c) inherits
d) uses

Answer 2

b) extends

The extends keyword is used to indicate that a class is inheriting from another class.

3. What will be the output of the following Java code?

 class Apple {
       public void print() { System.out.println("Apple"); }
   }
   class Banana extends Apple {
       public void print() { System.out.println("Banana"); }
   }
   public class Test {
       public static void main(String[] args) {
           Apple  apple = new Banana();
           apple.print();
       }
   }

Choose one option

a) Apple
b) Banana
c) No Output
d) Compilation Error

Answer 3

b) Banana

This is an example of dynamic method dispatch (polymorphism). The type of the object, not the reference type, determines which method is called.

4. If a class extends another class, which of the following members are inherited?

Choose one option

a) Only public methods
b) Public and protected members
c) Private methods
d) All members including private

Answer 4

b) Public and protected members

A subclass can inherit public and protected members of the superclass but not private members.

5. Which of these is correct way of inheriting class A by class B?

a) class B + class A {}
b) class B inherits class A {}
c) class B extends A {}
d) class B extends class A {}

Answer 5

c) class B extends A {}

The correct syntax for inheritance in Java is class B extends A {}. The extends keyword is used, and we refer to the superclass by name, not with the keyword class.

6. What will be the output of the following Java program?

 class Apple {
       public void print() { System.out.println("Apple"); }
   }
   class Banana extends Apple {
       public void print() { System.out.println("Banana"); }
   }
   public class Test {
       public static void main(String[] args) {
           Apple  apple = new Apple();
           apple.print();
       }
   }

Choose one option

a) Apple
b) Banana
c) No Output
d) Compilation Error

Answer 6

a) Apple

7. What will be the output of the following Java program?

class A {
    A(int x) { }
}

class B extends A {
    B(int x) {
        System.out.println("Constructor B");
    }
}

public class Test {
    public static void main(String[] args) {
        B obj = new B(10);
    }
}

Choose one option

a) It compiles without error.
b) It causes a compilation error.
c) It throws a runtime error.
d) It prints “Constructor B”

Answer 7

b) It causes a compilation error.

The constructor in B needs to explicitly call the constructor of A using super(x). This is required because A doesn’t have a no-argument constructor.

8. What will be the output?

class Parent {
    void method() {
        System.out.println("Parent method");
    }
}

class Child extends Parent {
}

public class Test {
    public static void main(String[] args) {
        Child obj = new Child();
        obj.method();
    }
}

Choose one option

a) Parent method
b) Child method
c) Compilation Error
d) Runtime Error

Answer 8

a) Parent method

Child doesn’t override method(), it inherits method() from Parent.

9. Which of the following statements about inheritance is false?

a) Java supports single inheritance.
b) Java allows multiple class inheritance using extends.
c) Interfaces can be used to achieve multiple inheritance.
d) The super keyword can be used to invoke the parent class constructor.

Answer 9

b) Java allows multiple class inheritance using extends.

Java does not allow multiple class inheritance using extends to avoid ambiguity issues. Instead, interfaces provide an alternative for multiple inheritance.

10. Which type of inheritance is demonstrated when a class inherits from a class that already inherits from another class?

a) Single inheritance
b) Multiple inheritance
c) Multilevel inheritance
d) Hierarchical inheritance

Answer 10

c) Multilevel inheritance

The type of inheritance demonstrated when a class inherits from a class that already inherits from another class is called multilevel inheritance. In this type of inheritance, a class is derived from a derived class, effectively creating a hierarchy of classes.

11. What is the keyword used in Java to prevent a class from being inherited?

Choose one option

a) abstract
b) final
c) static
d) private

Answer 11

b) final

The final keyword in Java is used to prevent a class from being inherited. When a class is declared as final, it cannot be extended by any other class.

12.  What is the purpose of using the `super` keyword in Java?

Choose one option

a) To create a new object instance
b) To call a constructor of the subclass
c) To refer to the current object’s superclass
d) To hide inherited methods

Answer 12

c) To refer to the current object’s superclass

The super keyword is used to access the superclass’s constructor or methods and can be used to invoke the superclass version of an overridden method.

13. Which of the following statements about the super keyword in Java is true?

Choose one option

a) The super keyword is used to call the parent class constructor.
b) The super keyword is used to access the methods and properties of the parent class.
c) The super keyword is used to create an instance of a child class.
d) The super keyword is not supported in Java.

Answer 13

b) The super keyword is used to access the methods and properties of the parent class.

The super keyword in Java is used to access the methods and properties of the parent class. It is often used to invoke the overridden methods of the parent class in the child class.

14. What will be the output of the following code?

  class Parent {
    public void print() {
        System.out.println("Parent");
    }
}

class Child extends Parent {
    public void print() {
        System.out.println("Child");
        super.print();
    }
}

public class Main {
    public static void main(String[] args) {
        Child child = new Child();
        child.print();
    }
}

Choose one option

a) Parent
Child
b) Child
Parent
c) Parent
d) Child

Answer 14

b) Child
Parent

This exception is thrown when a program attempts to use an object reference that has not been properly initialized.

15. What will be the result of the following code?

package pack1;
public class A {
    public void display() {
        System.out.println("Hello from A");
    }
}

package pack2;
import pack1.A;
public class B {
    public static void main(String args[]) {
        A obj = new A();
        obj.display();
    }
}

Choose one option

a) No output
b) Hello from A
c) Compiler error
d) Runtime error

Answer 15

b) Hello from A

Since class A is public and properly imported in pack2, there is no issue accessing it.

16. What is the result of the following code snippet?

class A 
    {
        int i;
        void display() 
        {
            System.out.println(i);
        }
    }    

    class B extends A 
    {
        int j;
        void display() 
        {
            System.out.println(j);
        }
    }    
    
   class Test
    {
        public static void main(String args[])
        {
            B obj = new B();
            obj.i=1;
            obj.j=2;   
            obj.display();     
        }
   }

Choose one option

a) 0
b) 1
c) 2
d) Compilation Error

Answer 16

c) 2

Class A & class B both contain display() method, class B inherits class A, when display() method is called by object of class B, display() method of class B is executed rather than that of Class A.

17.  What will be printed?

 class A 
    {
        int i;
    }    

    class B extends A 
    {
        int j;
        void display() 
        {
            super.i = j + 1;
            System.out.println(j + " " + i);
        }
    }    

    class Test 
    {
        public static void main(String args[])
        {
            B obj = new B();
            obj.i=1;
            obj.j=2;   
            obj.display();     
        }
   }

Choose one option

a) Hello
a) 2 2
b) 3 3
c) 2 3
d) 3 2

Answer 17

c) 2 3

Class A and Class B both contain a display() method. Class B inherits Class A. When the display() method is called by an object of Class B, the display() method of Class B is executed rather than that of Class A. The value of i is updated in the display() method using the super keyword.

18. What is polymorphism in Java?

a) A feature that allows a class to be abstract
b) A feature that allows one interface to be used for a general class of actions
c) A type of inheritance in Java
d) A way to modularize the code

Answer 18

b) A feature that allows one interface to be used for a general class of actions

Polymorphism allows methods to do different things based on the object it is acting upon, using a general interface for different underlying forms (data types).

 19.  How can you achieve polymorphism in Java?

a) By method overloading only
b) By method overriding only
c) By both method overloading and overriding
d) By using final classes

Answer 19

c) By both method overloading and overriding

Polymorphism can be achieved through method overloading (compile-time polymorphism) and method overriding (run-time polymorphism).

20.  Which of the following statements about multiple inheritance of interfaces is true?

Choose one option

a) It is allowed in Java
b) It is not allowed in Java
c) It leads to ambiguity
d) Only one interface can be inherited

Answer 20

a) It is allowed in Java

Java allows a class to implement multiple interfaces, enabling multiple inheritance of method signatures.

21. What is the output of the below program?

public class Parent {
    void m1(String x) {
        System.out.println("One");
    }
}

public class Derived extends Parent{
    public void m1(String x) {
        System.out.println("Two");
        super.m1(null);
    }
}

public class Test {
    public static void main(String[] args){
        Parent obj = new Derived();
        obj.m1(null);
    }
}

a) Two, One
b) One, Two
c) Compiler error
d) Runtime error

Answer 21

a) Two, One

The m1 method of Derived is executed first because Derived overrides m1. It prints “Two”. Then, super.m1(null) is executed within the m1 method of Derived, which calls the m1 method of the Parent class, printing “One”.

22. What will be the output of this program?

public class Test{

    void m1(String x){
        System.out.println("One");
    }
    
    protected void m1(String x, String y){
        System.out.println("Two");
    }
    
    public static void main(String[] args){
        Test obj = new Test();
        obj.m1("ABC");
        obj.m1("PQR", "XYZ");
    }
}

a) Two One
b) One Two
c) Compile time error
d) Runtime error

Answer 22

b) One Two

23. What is the output of the following program?

public class PolymorphismDemoClass {
    void add(int x, int y){
        System.out.println("1. Addition is: " +(x+y));
    }
    
   void add(int y, int x){
        System.out.println("2. Addition is: " +(x+y));
    }
    
   public static void main(String[] args){
        PolymorphismDemoClass obj = new PolymorphismDemoClass();
        obj.add(20, 30);
    }
}

a) Prints 2. Addition of two numbers: 50
b) Prints 1. Addition of two numbers: 50
c) Compile time error
d) Runtime error

Answer 23

c) Compile time error

24. What is the key difference between compile-time and runtime polymorphism in Java?

a) Compile-time polymorphism is implemented using method overriding, while runtime polymorphism is implemented using method overloading.
b) Compile-time polymorphism is determined during compilation, while runtime polymorphism is resolved at runtime.
c) Runtime polymorphism is faster than compile-time polymorphism.
d) Compile-time polymorphism is achieved using interfaces.

Answer 24

b) Compile-time polymorphism is determined during compilation, while runtime polymorphism is resolved at runtime.

Compile-time polymorphism (method overloading) is resolved at compile-time, while runtime polymorphism (method overriding) is determined during execution via dynamic method dispatch.

25. What will happen if two classes in different packages have the same name and are imported in a Java file?

a) Compilation error due to ambiguity.
b) The last imported class is used.
c) The first imported class is used.
d) Java automatically renames one class.

Answer 25

a) Compilation error due to ambiguity.

Java does not allow ambiguity in class names across packages. Fully qualified names must be used in such cases.

We would love to hear from you! Please leave your comments and share your scores in the section below

vibssingh

Java – Multiple Choice Questions and Answers – Exception Handling

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Welcome to the Java Quiz! This blog post features 25 multiple-choice questions that explore the exception handling in Java.

1. What is Exception in Java

a) An error that occurs during runtime 
b) An error that occurs during compilation
c) A warning issued by the compiler
d) A type of loop

Answer 1

a) An error that occurs during runtime 

2. Which of the following is the root class of the exception hierarchy in Java?

a) Exception
b) Throwable
c) Error
d) RuntimeException

Answer 2

b) Throwable

 The root class of the Java exception hierarchy is Throwable. Both Exception and Error are subclasses of Throwable.

3. What will be the output of the following Java code?

public class QAAutomation {
    
     public static void main(String[] args) {
        try {
            System.out.println("Inside try");
            throw new RuntimeException("Error");
        } finally {
            System.out.println("Inside finally");
        }
    }
}

Choose one option

a) Inside try
b) Inside try Inside finally
c) Inside try Inside finally RuntimeException
d) Compilation Error

Answer 3

c) Inside try Inside finally RuntimeException

The finally block executes even after an exception is thrown.

4. What will be the output of the following Java program?

 public class QAAutomation {
    
    static void method() throws Exception {
        throw new Exception("Error occurred");
    }

    public static void main(String[] args) {
        method();
    }
}

Choose one option

a) Compilation Error
b) Runtime error
c) Exception: Error occurred
d) Program runs successfully

Answer 4

a) Compilation Error

The method() declares throws Exception, but main() does not handle it, leading to a compilation error.

5. What is the difference between throw and throws?

a) throw is used to declare exceptions, throws is used to throw exceptions
b) throws is used to declare exceptions, throw is used to throw exceptions
c) Both are used to declare exceptions
d) Both are used to throw exceptions

Answer 5

b) throws is used to declare exceptions, throw is used to throw exceptions

throw is used inside a method to throw an exception, while throws is used in the method signature to declare possible exceptions.

6. What will be the output of the following Java program?

 class CustomException extends Exception {
    public CustomException(String message) {
        super(message);
    }
}

public class Test {
    public static void main(String[] args) {
        try {
            throw new CustomException("Custom error occurred");
        } catch (CustomException e) {
            System.out.println(e.getMessage());
        }
    }
}

Choose one option

a) Custom error occurred
b) Compilation Error
c) No Output
d) Runtime Exception

Answer 6

a) Custom error occurred

A custom exception is thrown and caught, and e.getMessage() prints the error message.

7. What will be the output of the following Java program?

public class Test {
    
    public static void main(String args[]) {
        try {
            int a, b;
            b = 0;
            a = 5 / b;
            System.out.print("A");
        } catch (ArithmeticException e) {
            System.out.print("B");
        } finally {
            System.out.print("C");
        }
    }
}

Choose one option

a) A
b) B
c) AC
d) BC

Answer 7

d) BC

The variable a is set to 0, in expression b = 5/a refers to dividing an int{5} with an int{0} which results in an ArithmeticException, which is caught by the catch statement and “B” is printed. Since the final block must be executed in any case . Hence “C” also prints after “B”.

8. What will be the output of the following Java program?

public class Test {
    public static void main(String args[])
    {
        try
        {
            int i, sum;
            sum = 10;
            for (i = -1; i < 3 ;++i)
                sum = (sum / i);
        }
        catch(ArithmeticException e)
        {
            System.out.print("0");
        }
        System.out.print(sum);
    }
}

Choose one option

a) 0
b) 05
c) Compilation Error
d) Runtime Error

Answer 8

c) Compilation Error

sum variable is declared in try block, but trying to access it outside the try-catch block.

9. Which of the following can be declared in a method’s `throws` clause?

a) RuntimeException
b) Error
c) IOException
d) None of the above

Answer 9

c) IOException

Checked exceptions like IOException must be declared in a method’s throws clause if not caught. RuntimeException and Error are typically not declared.

10. What happens if an exception is not caught in a Java program?

a) The program continues running as normal
b) The program stops execution
c) The exception is ignored
d) None of the above

Answer 10

b) The program stops execution

If an exception is not caught, program execution will halt, and the JVM will likely display an error message.

11. What will be the output?

public class Test{
    public static void main(String[] args) {
        try {
            System.exit(0);
        } finally {
            System.out.println("Finally executed");
        }
    }
}

Choose one option

a) Finally executed
b) No Output
c) Runtime Error
d) Compilation Error

Answer 11

b) No Output

System.exit(0) terminates the JVM, so the finally block does not execute.

12.  How many catch blocks can be associated with one try block?

Choose one option

a) Only one
b) One or more
c) None
d) Exactly two.

Answer 12

b) One or more

A try block can have multiple catch blocks to handle different types of exceptions.

13. Which block is always executed whether an exception is handled or not?

Choose one option

a) try
b) catch
c) finally
d) throw

Answer 13

c) finally

The finally block is always executed after the try and catch blocks, regardless of whether an exception was handled.

14. What will be the output of the following code?

  public class Test {
         public static void main(String[] args) {
             String str = null;
             try {
                 System.out.println(str.length());
             } catch (NullPointerException e) {
                 System.out.println("Caught a NullPointerException");
             }
         }
     }

Choose one option

a) NullPointerException
b) Caught a NullPointerException
c) IllegalArgumentException
d) IOException

Answer 14

b) Caught a NullPointerException

This exception is thrown when a program attempts to use an object reference that has not been properly initialized.

15. What will be the result of this expression?

import java.io.File;
import java.io.FileReader;
import java.io.IOException;

public class Test {
    public static void readFile() throws IOException {
        File file = new File("example.txt");
        FileReader reader = new FileReader(file);
        reader.close();
    }

    public static void main(String[] args) {
        try {
            readFile();
        } catch (IOException e) {
            System.out.println("IOException handled");
        }
    }
}

Choose one option

a) RuntimeException
b) NullPointerException
c) IOException handled
d) ArithmeticException

Answer 15

c) IOException handled

Checked exceptions, such as IOException, must be declared or handled explicitly.

16. What is the result of the following code snippet?

public class Test {
    
    public static void main(String[] args) {

        try {
            int[] numbers = {1, 2, 3};
            System.out.println(numbers[3]);
            int division = 10 / 0;
        } catch (ArrayIndexOutOfBoundsException e) {
            System.out.println("Array index is out of bounds");
        } catch (ArithmeticException e) {
            System.out.println("Cannot divide by zero");
        } finally {
            System.out.println("Finally block executed");
        }
        System.out.println("Rest of the program");
    }
}

Choose one option

a) Array index is out of bounds
Finally block executed
Rest of the program


b) Cannot divide by zero
Finally block executed
Rest of the program


c) Finally block executed
Cannot divide by zero
Rest of the program


d) Cannot divide by zero
Rest of the program

Answer 16

a) Array index is out of bounds
Finally block executed
Rest of the program

The code tries to access the fourth element (index 3) of a three-element array, which causes an ArrayIndexOutOfBoundsException. This is caught by the first catch block, which prints “Array index is out of bounds.” The finally block is always executed, so “Finally block executed” is printed next. The program then continues with “Rest of the program.”

17.  What will be the output of the below program?

public class Test {
    public static void main(String args[])
    {
        try
        {
            System.out.print("Hello" + " " + 1 / 0);
        }
        catch(ArithmeticException e)
        {
            System.out.print("World");
        }
    }
}

Choose one option

a) Hello
b) World
c) HelloWorld
d) Hello World

Answer 17

b) World

System.out.print() function first converts the whole parameters into a string and then prints, before “Hello” goes to output stream 1 / 0 error is encountered which is cached by catch block printing just “World”.

18. What does the `throws` keyword do?

a) It throws an exception
b) It declares that a method can throw exceptions
c) It defines a new exception
d) None of the above

Answer 18

b) It declares that a method can throw exceptions

The throws keyword is used in a method signature to declare that the method can throw specified exceptions.

 19.  Which exception is thrown when an object is attempted to be cast into a subclass it is not an instance of?

a) IllegalArgumentException
b) IndexOutOfBoundsException
c) ClassCastException
d) ClassNotFoundException

Answer 19

c) ClassCastException

ClassCastException is thrown to indicate that the code has attempted to cast an object to a class of which it is not an instance.

20. What is the output of the following code?

public class Test {

    public static void main(String[] args) {
        try {
            throw new Exception("First Exception");
        } catch (Exception e) {
            try {
                throw new Exception("Second Exception");
            } catch (Exception ex) {
                System.out.println(ex.getMessage());
            }
        }
    }
}

Choose one option

a) First Exception
b) Second Exception
c) First Exception followed by Second Exception
d) Second Exception followed by First Exception

Answer 20

b) Second Exception

The code throws the first exception, catches it, and then throws the second exception, which is caught and its message is printed.

21. What is the output of the below program?

public class Test {
    public static void main(String[] args) {
        try {
            throw new Error("Fatal error");
        } catch (Exception e) {
            System.out.println("Exception");
        } catch (Error e) {
            System.out.println("Error");
        }
    }
}

a) Exception
b) Error
c) Compiler error
d) The code will not compile.

Answer 21

b) Error

The code explicitly throws an Error with the message “Fatal error”. Since Error is a subclass of Throwable, it matches the catch block for Error, and “Error” is printed.

22. What will be the output of the below program?

public class Test {
    public static void main(String[] args) {
        try {
            int[] array = new int[5];
            System.out.println(array[5]);
        } catch (ArrayIndexOutOfBoundsException e) {
            System.out.println("ArrayIndexOutOfBoundsException");
        } finally {
            System.out.println("Finally block executed.");
        }
    }
}

a) ArrayIndexOutOfBoundsException
     Finally block executed.
b) ArrayIndexOutOfBoundsException
c) Finally block executed.
d) The code will not compile.

Answer 22

a) ArrayIndexOutOfBoundsException
     Finally block executed.

The code attempts to access an element at index 5 in the array which is not available. Hence it raises an ArrayIndexOutOfBoundsException. The catch block is executed, and then the finally block is executed.

23. What is the output of the following program?

public class Test {
    public static void main(String[] args) {
        try {
            throw new NullPointerException();
        } catch (RuntimeException e) {
            System.out.println("RuntimeException");
        } catch (Exception e) {
            System.out.println("Exception");
        }
    }
}

a) RuntimeException
b) Exception
c) NullPointerException
d) The code will not compile.

Answer 23

a) RuntimeException

The code explicitly throws a NullPointerException, which is a subclass of RuntimeException. Since the catch block for RuntimeException is defined first, it is executed.

24. Which of the following is true about custom exceptions?

a) Custom exceptions cannot extend Exception class
b) Custom exceptions are always checked exceptions
c) Custom exceptions can extend Exception or RuntimeException
d) Custom exceptions do not require a constructor

Answer 24

c) Custom exceptions can extend Exception or RuntimeException

Custom exceptions can extend Exception (checked) or RuntimeException (unchecked).

25. Which of the following exception must be either caught or declared to be thrown in Java?

a) NullPointerException
b) ArrayIndexOutOfBoundsException
c) FileNotFoundException 
d) ArithmeticException

Answer 25

c) FileNotFoundException 

FileNotFoundException is a checked exception in Java, hence it must be either caught or declared to be thrown.

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