Common interview questions for java developer

Posted in Programming By Deven SharmaPosted on

Certainly! Here are some common interview questions for Java developers:

  1. Basic Java Concepts:
    • Explain the difference between == and .equals() method.
    • What is the difference between ArrayList and LinkedList?
    • What are the basic principles of Object-Oriented Programming (OOP)?
    • Explain the concept of polymorphism in Java.
    • What is the significance of the static keyword in Java?
  2. Java Language Fundamentals:
    • How does garbage collection work in Java?
    • Describe the significance of the final keyword in Java.
    • Explain the difference between checked and unchecked exceptions.
    • What is the purpose of the transient keyword?
    • How is multithreading achieved in Java? Explain synchronization.
  3. Java Collections:
    • Compare HashMap and HashTable.
    • What is the difference between ArrayList and LinkedList?
    • Explain the differences between Set, List, and Map.
    • How does the compareTo() method work in Java?
  4. Java APIs:
    • Explain the purpose of the java.lang.StringBuilder class.
    • How does the equals() method work for strings in Java?
    • What is the significance of the java.util.Collections class?
    • Describe the role of the Comparable and Comparator interfaces.
  5. Exception Handling:
    • What is the purpose of the finally block in exception handling?
    • Explain the difference between throw and throws in Java.
    • How do you handle exceptions in a multithreaded environment?
  6. Java EE (Enterprise Edition):
    • What is the difference between Servlet and JSP?
    • Explain the concept of JavaBeans.
    • Describe the purpose of the ServletContext in a Java web application.
    • How does JDBC (Java Database Connectivity) work?
  7. Spring Framework:
    • What is the Spring framework, and what are its key features?
    • Explain the concept of dependency injection in Spring.
    • Differentiate between Spring MVC and Spring Boot.
    • What is the purpose of the @Autowired annotation?
  8. Hibernate (Object-Relational Mapping):
    • What is Hibernate, and why would you use it?
    • Explain the concept of ORM (Object-Relational Mapping).
    • What is the purpose of the Hibernate SessionFactory?
    • How do you map a Java class to a database table using Hibernate?
  9. Unit Testing:
    • What is JUnit, and how do you use it for unit testing in Java?
    • Explain the concept of test-driven development (TDD).
  10. Design Patterns:
    • Describe the Singleton design pattern and provide an example.
    • Explain the Observer pattern.
    • What is the purpose of the Factory method pattern?

These questions cover a range of topics and can help assess a candidate’s knowledge and experience as a Java developer. Depending on the specific role and the company’s needs, the interviewer may focus more on certain areas.

Common interview questions for java developer
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