Top 15 Java Interview Questions and Answers You Must Know in 2025
Ace your next Java developer interview with these 15 most-asked Java interview questions and expert answers in 2025. Perfect for freshers and experienced candidates.
Java continues to dominate the world of programming with its reliability, scalability, and massive enterprise usage. Whether you’re a fresher or an experienced developer, Java interviews can be tricky — especially in 2025, where employers are focusing on problem-solving skills and core Java concepts.
In this blog, we’ve compiled the Top 15 most frequently asked Java interview questions and answers to help you crack your next interview confidently.
Top 15 Java Interview Questions & Answers for 2025
1. What are the key features of Java?
Answer:
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Platform Independent
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Object-Oriented
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Robust & Secure
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Multithreaded
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Distributed
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High Performance using JIT compiler
2. What is the difference between JDK, JRE, and JVM?
Answer:
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JDK (Java Development Kit): Provides tools to develop Java applications.
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JRE (Java Runtime Environment): Provides libraries to run Java applications.
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JVM (Java Virtual Machine): Converts bytecode into machine code during runtime.
3. Explain the concept of OOPs in Java.
Answer:
Java is an Object-Oriented Programming language. Key principles include:
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Inheritance
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Encapsulation
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Abstraction
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Polymorphism
4. What is the difference between ‘==’ and .equals() in Java?
Answer:
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==compares references. -
.equals()compares the content of two objects.
5. What is the use of the ‘final’ keyword in Java?
Answer:
It is used to declare constants, prevent method overriding, and inheritance of classes.
6. What is the difference between an abstract class and an interface?
Answer:
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Abstract class can have method implementations.
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Interface only has method declarations (until Java 8, where default methods were added).
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A class can implement multiple interfaces but only extend one abstract class.
7. What are checked and unchecked exceptions in Java?
Answer:
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Checked Exceptions: Handled during compile time (e.g., IOException).
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Unchecked Exceptions: Handled during runtime (e.g., NullPointerException).
8. What is multithreading in Java?
Answer:
Multithreading allows concurrent execution of two or more parts of a program for maximum utilization of CPU.
9. What is the use of the this keyword in Java?
Answer:
It refers to the current instance of the class and is used to differentiate between instance variables and parameters.
10. How does garbage collection work in Java?
Answer:
Java uses an automatic garbage collector to manage memory and delete unused objects to prevent memory leaks.
11. What is the difference between ArrayList and LinkedList?
Answer:
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ArrayList is faster for searching and indexing.
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LinkedList is faster for insertion and deletion.
12. What is method overloading and method overriding?
Answer:
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Overloading: Same method name, different parameters (within the same class).
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Overriding: Subclass redefines a method from the parent class.
13. What is a constructor in Java?
Answer:
A constructor is a block of code used to initialize an object and is called when the object is created.
14. Explain ‘super’ keyword in Java.
Answer:
Used to refer to the immediate parent class object. Commonly used to access parent class methods or constructors.
15. What is a singleton class in Java?
Answer:
A singleton class allows only one instance to be created and provides a global access point to that instance.
Conclusion:
Being well-prepared with these common Java interview questions and answers will surely give you an edge in your next interview. Java remains one of the top programming languages in demand for backend, full stack, and enterprise-level development roles.
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FAQs:
Q: Are these Java interview questions good for freshers?
Yes, they are beginner-friendly and often asked in entry-level tech interviews.
Q: How should I prepare for Java coding rounds?
Focus on data structures, algorithms, OOPs concepts, and practice on platforms like LeetCode or HackerRank.
