Coforge Senior Java Developer Interview Questions, Process, and Tips

A set of interview questions for a Senior Java Developer position.

• Singleton class in Java is a class that allows only one instance of itself to be created.

• String is immutable in Java because it ensures thread safety and allows for efficient memory management.

• ArrayList and LinkedList are both implementations of the List interface, but differ in their underlying data structure and performance characteristics.

• IOC (Inversi...read more

ArrayList is implemented as a resizable array while LinkedList is implemented as a doubly linked list.

• ArrayList provides constant time for accessing elements while LinkedList provides constant time for adding or removing elements.

• ArrayList is better for storing and accessing data while LinkedList is better for manipulating data.

• ArrayList is faster for iterating through elements while LinkedList is faster for adding or

Program to filter employees using Java streams

• Create a list of employees

• Use stream() method to convert list to stream

• Use filter() method to filter employees based on condition

• Use collect() method to convert stream back to list

Spring Boot has various exceptions for different scenarios.

• DataAccessException - for database access errors

• HttpMessageNotReadableException - for errors in HTTP message conversion

• MethodArgumentNotValidException - for validation errors in request parameters

• NoSuchBeanDefinitionException - for errors in bean configuration

• UnauthorizedException - for authentication and authorization errors

Changing annotations on Spring Boot classes can have significant impact on the application.

• Changing annotations can affect the behavior of the application

• Annotations can control the lifecycle of beans, security, caching, etc.

• Removing or modifying annotations can cause runtime errors

• Adding new annotations can introduce new functionality

• Annotations can affect the performance of the application

Setting port number as 0 in Spring Boot for a service

• Setting port number as 0 allows the operating system to choose an available port

• This is useful when running multiple instances of the same service on the same machine

• To set port number as 0 in Spring Boot, add 'server.port=0' to application.properties or application.yml