152 interview questions on Java for developers (2025)

28 votes2808 runs

Pierreat Sep 19, 2022

16 votes3326 runs

control flow

Thomas De verdièreat Dec 16, 2021

13 votes1418 runs

12 votes3334 runs1 comment

serialization

Thomas De verdièreat Jan 4, 2022

12 votes3273 runs0 comment

Thomas De verdièreat Jan 4, 2022

12 votes3219 runs0 comment

Thomas De verdièreat Jan 4, 2022

12 votes3169 runs0 comment

Thomas De verdièreat Dec 16, 2021

12 votes2720 runs

Pierreat Sep 19, 2022

11 votes3335 runs

serialization

Thomas De verdièreat Dec 2, 2021

11 votes3231 runs0 comment

design pattern

Thomas De verdièreat Jan 4, 2022

11 votes2614 runs

concatenation

Pierreat Jan 4, 2022

10 votes3376 runs0 comment

Thomas De verdièreat Jan 4, 2022

9 votes3149 runs0 comment

Thomas De verdièreat Jan 4, 2022

8 votes3300 runs0 comment

Thomas De verdièreat Jan 4, 2022

8 votes3189 runs0 comment

Thomas De verdièreat Jan 4, 2022

8 votes2630 runs0 comment

Pierreat Jan 4, 2022

7 votes3306 runs0 comment

Thomas De verdièreat Dec 16, 2021

7 votes3189 runs1 comment

Thomas De verdièreat Jan 4, 2022

7 votes3152 runs0 comment

design patterns

Thomas De verdièreat Jan 4, 2022

7 votes2661 runs0 comment

Pierreat Sep 19, 2022

152 interview questions on Javafor developers (2025)

Test your technical skills before an interview of Java with 152 corrected questions. Beginner, Intermediate or Expert level.

152 interview questions on Javafor developers (2025)

Test your technical skills before an interview of Java with 152 corrected questions. Beginner, Intermediate or Expert level.

Write a Java program that prints 'welovedev'.

How many times is the condition `(a++ < 15)` evaluated in the following code? ```java int a = 3; while (a++ < 15) { if ((a++ % 5) == 0) break; } ```

What is the difference between an interface and an abstract class in Java?

Serialization can be customized with the Externalizable interface

A monitor in Java

What does the final keyword mean in front of a method in Java?

How many instance of Integer cannot be freed from memory?

How should a package be named in Java?

What is the error message when you try to serialize a class that does not implement Serializable?

What "design pattern" makes it possible to offer a means of treating the elements of a tree without worrying about the course?

How to concatenate two strings of characters in Java?

A Customer class has the com.company.model package.

Which of these classes is the most suitable for composing a character string from several elements concatenated to each other?

A “synchronized” method

What is the classpath for?

Add elements to an ArrayList in Java

Write a finalizer in Java.

What is the superclass of Integer, Long, Byte, BigDecimal and Short in Java?

What design pattern will you use to dynamically add capabilities to an object in Java?

Are arrays primitives types in Java?