In this Java interview questions blog, you will find the most asked questions and answers for Java interviews. Practicing these questions will help crack the interview. So, let's get started.

1. Top 30 Java Phone Interview Questions for Fresher
( 1 To 2 Years Experienced )
In this Java interview questions blog, you will find the most asked questions and answers
for Java interviews. Practicing these questions will help crack the interview. So, let's get
started.
1. List down the main features of Java.
• Object-Oriented programming language
• Easy to learn
• Distributed
• Multithreaded
• Platform-independent
• Robust
• Portable
• Secure
2. What is an Array?
An Array is a container object that contains a specific number of values of a single data type.
3. Can you declare an Array without Array size?
No, you cannot declare an Array without Array size.
4. Explain the meaning of Object-Oriented Programming.
Object-oriented programming is based on the concepts of 'objects or 'data' instead of
functions and logic.
5. What are the fundamental OOP concepts?
There are four OOPS concepts- Inheritance, Encapsulation, Polymorphism, and Abstraction.
6. What is multithreaded programming?
In multithreaded programming, multiple threads run to execute the task simultaneously.
7. Why is Java String immutable?
The Java String is immutable for several reasons: synchronization and concurrency,
performance, security, caching, and class loading.
8. What is abstraction?
Abstraction is a concept of hiding implementation details from the user and giving access to
only key characteristics.
9. Explain the Inheritance concept?
Inheritance allows one java class to inherit the properties or behavior of another class.

2. Top 30 Java Phone Interview Questions for Fresher
( 1 To 2 Years Experienced )
10. What is an Object in Java?
The object is an instance or member of a Java class. It contains a real-world object's basic
properties, identity, and behavior.
11. When to use abstract class and interface?
Abstract classes are primarily used for closely related objects, while interfaces are used to
provide a common functionality to unrelated classes.
12. What is the singleton class in Java?
A class that can have one instance at any given time in one JVM is a singleton class.
13. What is the difference between List and Set?
A list is an ordered sequence that maintains the elements in order of insertion. On the other
hand, the Set is an unordered collection where elements are not maintained.
14. What do you mean by the method overloading?
If a class consists of multiple methods of the same name but different parameters, it means
method overloading.
15. Explain method overriding in Java?
In Java, method overriding happens when the subclass (child class) method is similar to the
parent class.
16. Can you override the overloaded method in Java?
Yes, you can override the overloaded method.
17. Can you overload the main() method?
Yes, you can overload the main method.
18. Explain the difference between Collection and Collections.
A Collection is an interface, while Collections is a utility class.
19. Differentiate between constructor and method?
The constructor helps to initialize an object, while the method helps exhibit an object's
functionality.
20. What is the difference between String, StringBuilder, and StringBuffer?
The string is immutable in Java, while StringBuilder and StringBuffer are mutable classes.
21. What are static and non-static methods?

3. Top 30 Java Phone Interview Questions for Fresher
( 1 To 2 Years Experienced )
Static methods belong to a class, whereas non-static methods belong to an object.
22. State the difference between Error and Exception?
Error is generated due to a lack of system resources. On the other hand, the exception is
caused due to problem in code.
23. How method overloading and method overriding are different?
In method overloading, methods have the same name but different signatures while in method
overriding, methods have the same name and signature.
24. What is synchronization in Java?
Synchronization is a technique where only one thread can be used at a time to complete the
task.
25. What are the ways to create threads in Java?
Threads in Java can be created by
a. By implementing a Runnable interface
b. By extending the Thread class
26. Define the garbage collection of Java?
Garbage collection is a process where the programs automatically perform memory
management.
27. Why use the final keyword in Java?
The final keyword in Java helps create constants and prevents inheritance and methods from
being overridden.
28. What is JVM?
Java virtual machine or JVM compiles and interprets the java code.
29. What is cloning in Java?
Cloning is a method in which an exact copy of an object is created.
30. How do ArrayLists and LinkedLists differ?
ArrayList implements only List, whereas LinkedList implements both List and Queue.
So, this brings us to the close of the top 30 Java interview questions. These questions will
help in preparation for Java interview.

4. Top 30 Java Phone Interview Questions for Fresher
( 1 To 2 Years Experienced )