Java Back End Developer Interview Questions

140 java back end developer interview questions shared by candidates

What is the difference between Java and JavaScript? Some basic knowledge on multi-thread, can't remember. If you have 1000 2d points as a tuple like (x1, y1) how could you store these points and count the number of occurrence of each position efficiently?
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Java Back-end Developer

Interviewed at Canva

3.9
Sep 15, 2021

What is the difference between Java and JavaScript? Some basic knowledge on multi-thread, can't remember. If you have 1000 2d points as a tuple like (x1, y1) how could you store these points and count the number of occurrence of each position efficiently?

1) What are stream and collection stream 2)How to create custom immutable class? 3)Can we override static method and why? 4)Hashmap and LinkedHashmap Difference? 5)What is concurrentHashmap? 6)Difference between ArrayList and LinkedList and in what scenarios the are preffered to be used? 7)What are different HTTP methods? 8)What are Object methods? 9)Which Junit version you have worked on? 10)Anotations in Junit? 11)In what scenario you use @BeforeAll? 12)Git commands you have used? 13)What branching strategy you have used in your previous project? 14)If we make some changed in local repository what wll be the first command that we will execute? 15)Do you have any idea on SonarQube? 16)Check if the given smaller string is substring of larger string without using inbuilt methods. 17)Java code for most occuring character in a string?
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Java Back-end Developer

Interviewed at Pratiti Technologies

3.5
Nov 2, 2025

1) What are stream and collection stream 2)How to create custom immutable class? 3)Can we override static method and why? 4)Hashmap and LinkedHashmap Difference? 5)What is concurrentHashmap? 6)Difference between ArrayList and LinkedList and in what scenarios the are preffered to be used? 7)What are different HTTP methods? 8)What are Object methods? 9)Which Junit version you have worked on? 10)Anotations in Junit? 11)In what scenario you use @BeforeAll? 12)Git commands you have used? 13)What branching strategy you have used in your previous project? 14)If we make some changed in local repository what wll be the first command that we will execute? 15)Do you have any idea on SonarQube? 16)Check if the given smaller string is substring of larger string without using inbuilt methods. 17)Java code for most occuring character in a string?

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