30 Most Common Java Interview Questions for Freshers (With Answers)

If you’re a fresher preparing for Java interviews, this guide is for you. We’ve compiled the top 30 Java interview questions for freshers—covering everything from basic syntax to OOPs, exception handling, and more. This post covers the most common Java interview questions for freshers—with real-world examples, concise answers, and code snippets. Whether you’re preparing for an internship or a full-time job, mastering these questions can give you a strong edge.

📚 Java Interview Questions for Freshers (With Answers)

1. What is Java?

Java is a high-level, object-oriented, platform-independent programming language developed by Sun Microsystems in 1995.

2. What are the features of Java?

• Platform Independent
• Object-Oriented
• Simple and Secure
• Robust and Portable
• High Performance
• Multi-threaded

3. What is the difference between JDK, JRE, and JVM?

• JDK (Java Development Kit): Contains tools and JRE to develop Java applications
• JRE (Java Runtime Environment): Provides JVM and libraries to run Java programs
• JVM (Java Virtual Machine): Converts bytecode into machine code for execution

4. What is the main() method in Java?

It’s the entry point of a Java program.

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

5. What is the difference between == and .equals()?

• == checks memory address (reference comparison)
• .equals() checks actual content (value comparison)

6. What is a Class and Object?

• Class is a blueprint or template.
• Object is an instance of a class created using the new keyword.

7. What is Inheritance?

Inheritance allows one class to inherit the fields and methods of another using the extends keyword.

8. What is Method Overloading and Overriding?

• Overloading: Same method name, different parameters (compile-time polymorphism)
• Overriding: Same method name and parameters in subclass (run-time polymorphism)

9. What is a Constructor?

A special method that is used to initialize objects. It has the same name as the class and no return type.

10. What is an Interface in Java?

An interface contains only abstract methods and constants. A class implements an interface to provide method definitions.

11. What are Access Modifiers in Java?

• private: within the same class
• default: within the same package
• protected: package + subclasses
• public: accessible from everywhere

12. What is the difference between Array and ArrayList?

Feature	Array	ArrayList
Size	Fixed	Dynamic
Type	Primitives & Objects	Objects only
Flexibility	Low	High

13. What is the use of the this keyword?

this refers to the current object of the class and helps differentiate between local and instance variables.

14. What is a static block?

It is used to initialize static variables. It runs once when the class is loaded.

static {
    System.out.println("Static block executed");
}

15. What is abstraction?

Abstraction is hiding implementation details and showing only essential features using abstract classes or interfaces.

16. What is encapsulation?

Encapsulation is the process of wrapping data (variables) and code (methods) into a single unit (class) and restricting access via access modifiers.

17. What is polymorphism?

Polymorphism means one task can be performed in many ways.

• Compile-time: Method overloading
• Run-time: Method overriding

18. What are wrapper classes?

Wrapper classes convert primitives into objects:

• int → Integer
• char → Character
• double → Double

19. What is type casting in Java?

Type casting converts one data type to another.

double d = 9.7;
int i = (int) d; // i = 9

20. What is the final keyword?

• final variable: Constant
• final method: Cannot be overridden
• final class: Cannot be extended

21. What is the difference between break and continue?

• break: exits the loop
• continue: skips the current iteration

22. Can a class have multiple constructors?

Yes. Constructor overloading allows a class to have multiple constructors with different parameter lists.

23. What is a package in Java?

A package is a namespace used to group related classes and interfaces.

package com.example.myapp;

24. What is exception handling?

Java provides try-catch blocks to handle runtime exceptions gracefully.

try {
    int x = 5 / 0;
} catch (ArithmeticException e) {
    System.out.println("Cannot divide by zero.");
}

25. What is the difference between checked and unchecked exceptions?

Type	Example	Checked at Compile Time
Checked	IOException, SQLException	Yes
Unchecked	NullPointerException	No

26. What is garbage collection in Java?

Garbage collection is the automatic process of identifying and removing unused objects from memory to free resources.

27. Can a constructor be private?

Yes. Private constructors are used in Singleton design patterns to restrict object creation.

28. What is the difference between throw and throws?

• throw is used to explicitly throw an exception
• throws declares exceptions a method might throw

29. What is a marker interface?

An interface that has no methods. It’s used to provide metadata to classes, like Serializable.

30. Can we overload the main method?

Yes, but the JVM always looks for the standard:

public static void main(String[] args)

Other overloads won’t be executed by default.

✅ Final Thoughts

Cracking your first Java interview may feel overwhelming, but with this Java interview questions for freshers guide, you’re already ahead of the curve.

Keep learning, stay confident—and go ace that interview! 💼

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