157 interview questions on Java for developers (2025)

32 votes2998 runs

Pierreat Sep 19, 2022

17 votes3448 runs

control flow

Thomas De verdièreat Dec 16, 2021

15 votes1621 runs

14 votes3452 runs1 comment

serialization

Thomas De verdièreat Jan 4, 2022

14 votes3331 runs0 comment

Thomas De verdièreat Jan 4, 2022

14 votes3293 runs0 comment

Thomas De verdièreat Dec 16, 2021

13 votes2904 runs

Pierreat Sep 19, 2022

12 votes3490 runs0 comment

Thomas De verdièreat Jan 4, 2022

12 votes3451 runs

serialization

Thomas De verdièreat Dec 2, 2021

12 votes3382 runs0 comment

Thomas De verdièreat Jan 4, 2022

11 votes3336 runs0 comment

design pattern

Thomas De verdièreat Jan 4, 2022

11 votes2779 runs

concatenation

Pierreat Jan 4, 2022

10 votes2813 runs0 comment

Pierreat Jan 4, 2022

9 votes3423 runs0 comment

Thomas De verdièreat Jan 4, 2022

9 votes3271 runs0 comment

Thomas De verdièreat Jan 4, 2022

9 votes3236 runs2 comments

Thomas De verdièreat Jan 4, 2022

8 votes3430 runs0 comment

Thomas De verdièreat Dec 16, 2021

8 votes3294 runs0 comment

Thomas De verdièreat Jan 4, 2022

8 votes3240 runs0 comment

Thomas De verdièreat Jan 4, 2022

7 votes3319 runs0 comment

Thomas De verdièreat Jan 4, 2022

157 interview questions on Javafor developers (2025)

Test your technical skills before an interview of Java with 157 corrected questions. Beginner, Intermediate or Expert level.

157 interview questions on Javafor developers (2025)

Test your technical skills before an interview of Java with 157 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

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?

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 monitor in Java

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

A “synchronized” method

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?

Write a finalizer in Java.

What is the classpath for?

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

Create an instance of ArrayList in Java