157 interview questions on Java for developers (2025)

32 votes2990 runs

Pierreat Sep 19, 2022

17 votes3444 runs

control flow

Thomas De verdièreat Dec 16, 2021

15 votes1613 runs

14 votes3447 runs1 comment

serialization

Thomas De verdièreat Jan 4, 2022

14 votes3329 runs0 comment

Thomas De verdièreat Jan 4, 2022

14 votes3287 runs0 comment

Thomas De verdièreat Dec 16, 2021

13 votes2899 runs

Pierreat Sep 19, 2022

12 votes3487 runs0 comment

Thomas De verdièreat Jan 4, 2022

12 votes3446 runs

serialization

Thomas De verdièreat Dec 2, 2021

12 votes3377 runs0 comment

Thomas De verdièreat Jan 4, 2022

11 votes3333 runs0 comment

design pattern

Thomas De verdièreat Jan 4, 2022

11 votes2774 runs

concatenation

Pierreat Jan 4, 2022

10 votes2808 runs0 comment

Pierreat Jan 4, 2022

9 votes3419 runs0 comment

Thomas De verdièreat Jan 4, 2022

9 votes3267 runs0 comment

Thomas De verdièreat Jan 4, 2022

9 votes3232 runs2 comments

Thomas De verdièreat Jan 4, 2022

8 votes3425 runs0 comment

Thomas De verdièreat Dec 16, 2021

8 votes3289 runs0 comment

Thomas De verdièreat Jan 4, 2022

7 votes3317 runs0 comment

Thomas De verdièreat Jan 4, 2022

7 votes3308 runs1 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?

Create an instance of ArrayList in Java

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