10+ Capgemini Interview Questions and Answers

EnableAutoConfiguration enables auto-configuration of Spring Boot application while ComponentScan scans for Spring components.

• EnableAutoConfiguration automatically configures Spring Boot application based on classpath and other settings.

• ComponentScan scans for Spring components and registers them as beans.

• EnableAutoConfiguration is used in main application class while ComponentScan can be used in any configuration class.

• EnableAutoConfiguration can be disabled using @SpringBoo...read more

A functional interface is an interface with only one abstract method. It can be implemented using lambda expressions.

• Functional interfaces are used in Java 8's functional programming features.

• Examples of functional interfaces include Runnable, Comparator, and Callable.

• To create your own functional interface, use the @FunctionalInterface annotation.

• The interface should have only one abstract method, and can have default and static methods.

• Lambda expressions can be used to impl...read more

Stream class methods include read, write, seek, tell, flush, and more.

• read() - reads data from the stream

• write() - writes data to the stream

• seek() - moves the stream position to a specified location

• tell() - returns the current position in the stream

• flush() - flushes any buffered data to the stream

• eof() - returns true if the end of the stream has been reached

• good() - returns true if the stream is in a good state

• fail() - returns true if a read or write operation failed

• clear() -...read more

Transactions in microservices ensure data consistency and integrity.

• Use distributed transactions to ensure atomicity across multiple services.

• Implement compensating transactions to handle failures and rollbacks.

• Use event-driven architecture to maintain consistency between services.

• Consider using a Saga pattern to manage long-running transactions.

• Avoid two-phase commit as it can lead to performance issues and scalability problems.

The @Transactional annotation is used in Spring to manage transactions in a declarative way.

• It is used to define the scope of a transaction.

• It can be applied at the class or method level.

• It supports various attributes like propagation, isolation, timeout, and read-only.

• It can be used with different transaction managers like JDBC, Hibernate, JPA, etc.

• It rolls back the transaction if an exception is thrown.

• It can be used with AOP to provide transaction management.

• Example: @Tran...read more

Future is an interface while CompletableFuture is a class that implements Future and provides additional methods.

• Future is a basic interface for asynchronous programming in Java

• CompletableFuture is a class that implements Future and provides additional methods like thenApply(), thenAccept(), etc.

• CompletableFuture can be used to chain multiple asynchronous operations

• CompletableFuture can also be used to handle exceptions in asynchronous programming

• CompletableFuture is more fle...read more

Java8 introduced several new features including lambda expressions, streams, and default methods.

• Lambda expressions allow for functional programming and simplify code.

• Streams provide a way to process collections of data in a functional way.

• Default methods allow for adding new methods to interfaces without breaking existing implementations.

• Other features include the Date and Time API, Nashorn JavaScript engine, and improved security.

• Java8 also introduced the concept of Optiona...read more

HTTP methods are used to specify the type of action to be performed on a resource.

• GET - retrieve information from the server

• POST - submit data to the server

• PUT - update a resource on the server

• DELETE - remove a resource from the server

• HEAD - retrieve headers from the server

• OPTIONS - retrieve the supported HTTP methods for a resource

• PATCH - update a resource partially on the server

Executor framework is a Java framework that provides a way to execute tasks asynchronously using a thread pool.

• It provides a way to manage threads and execute tasks in a thread pool

• It allows for better resource management and improved performance

• It supports different types of thread pools such as fixed, cached, and scheduled

• Example: Executors.newFixedThreadPool(10) creates a thread pool with 10 threads

Aggregation and composition are two types of relationships between objects in object-oriented programming.

• Aggregation is a relationship where one object is a container for other objects, but the contained objects can exist independently.

• Composition is a relationship where one object is composed of other objects, and the composed objects cannot exist independently.

• Aggregation is represented by a 'has-a' relationship, while composition is represented by a 'part-of' relationship...read more