159 interview questions on Java for developers (2026)

37 votes3242 runs

Pierreat Sep 19, 2022

17 votes3605 runs

control flow

Thomas De verdièreat Dec 16, 2021

16 votes3138 runs

Pierreat Sep 19, 2022

15 votes1881 runs

14 votes3624 runs1 comment

serialization

Thomas De verdièreat Jan 4, 2022

14 votes3554 runs0 comment

Thomas De verdièreat Jan 4, 2022

14 votes3506 runs0 comment

Thomas De verdièreat Jan 4, 2022

14 votes3445 runs0 comment

Thomas De verdièreat Dec 16, 2021

12 votes3645 runs0 comment

Thomas De verdièreat Jan 4, 2022

12 votes3606 runs

serialization

Thomas De verdièreat Dec 2, 2021

11 votes3600 runs0 comment

Thomas De verdièreat Jan 4, 2022

11 votes3501 runs0 comment

design pattern

Thomas De verdièreat Jan 4, 2022

11 votes2987 runs

concatenation

Pierreat Jan 4, 2022

10 votes3040 runs0 comment

Pierreat Jan 4, 2022

9 votes3422 runs0 comment

Thomas De verdièreat Jan 4, 2022

9 votes3392 runs2 comments

Thomas De verdièreat Jan 4, 2022

9 votes3062 runs0 comment

Pierreat Sep 19, 2022

8 votes3588 runs0 comment

Thomas De verdièreat Dec 16, 2021

8 votes3456 runs0 comment

Thomas De verdièreat Jan 4, 2022

8 votes3401 runs0 comment

Thomas De verdièreat Jan 4, 2022

159 interview questions on Javafor developers (2026)

Test your technical skills before an interview of Java with 159 corrected questions. Beginner, Intermediate or Expert level.

159 interview questions on Javafor developers (2026)

Test your technical skills before an interview of Java with 159 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; } ```

How should a package be named in Java?

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?

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

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

A “synchronized” method

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?

Add elements to an ArrayList in Java

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

What does the following code show?

Are arrays primitives types in Java?

Write a finalizer in Java.

What is the classpath for?

Java 5: where to place the "@Override" tag and why?