Java Backend Developer Interview Questions

320 java backend developer interview questions shared by candidates

1. Difference between Arraylist and linkedlist. 2. What is the time complexity of insertion in linkedlist? 3. Which one do you prefer in which condition? 4. Which one do you use to insert an array of integers? 5. Given two lists - remove all the elements of second list from first list. 6. Employee class - Employee1 emp1 = ID:1, name : ABC Employee2 emp2 = ID:1, name : ABC Treemap map = new TreeMap<>(); map.put(emp1,7); map.put(emp2,8); Is this allowed? What will be the size of the treemap in this case? 7. Internal implementation of put method in treemap. 8. Internal implementation of hashcode and equals in object class. 9. Time complexity of removeAll() in Linkedlist
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Java Backend Developer ()

Interviewed at Wissen Infotech

3.8
Jan 14, 2021

1. Difference between Arraylist and linkedlist. 2. What is the time complexity of insertion in linkedlist? 3. Which one do you prefer in which condition? 4. Which one do you use to insert an array of integers? 5. Given two lists - remove all the elements of second list from first list. 6. Employee class - Employee1 emp1 = ID:1, name : ABC Employee2 emp2 = ID:1, name : ABC Treemap map = new TreeMap<>(); map.put(emp1,7); map.put(emp2,8); Is this allowed? What will be the size of the treemap in this case? 7. Internal implementation of put method in treemap. 8. Internal implementation of hashcode and equals in object class. 9. Time complexity of removeAll() in Linkedlist

Tech Interview Question- OOPS- Abstraction, Inheritance, Polymorphism, Encapsulation. Inheritance VS polymorphism types of polymorphirm overloading, overriding. function on both. Question on ternary operator SQL- Indexing DDL VS DML Normalisation vs denormalisation Sharding SQL queries todo. What to do when db can handle only 100 votes but 1000 are coming from bank. Explain the internship. DSA- Stacks vs Queues. explain Binary Search, time complexity. Merge sort- nlogn divide and conquer. Recursion- Explain, base cases. Work Sample Questions Explain the aproach for the problem statement, Scopes of improvements for project Why Javascript, How can project can handle the multiple inputs, JAVA vs JS, any online tool that does the same job What is nosql, what does DB offer(ACID), why a web application, what is a web app which works on mobile- responsive. Individual contributions, any question(can we change the role), more question on stroage of files. code related question on async js,promises, settimeout, how to fix it, use of global array. optimization, performance, handling huge data, getting out the right data.
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Graduate Backend Developer - Java

Interviewed at BlueOptima

3.3
Jul 31, 2021

Tech Interview Question- OOPS- Abstraction, Inheritance, Polymorphism, Encapsulation. Inheritance VS polymorphism types of polymorphirm overloading, overriding. function on both. Question on ternary operator SQL- Indexing DDL VS DML Normalisation vs denormalisation Sharding SQL queries todo. What to do when db can handle only 100 votes but 1000 are coming from bank. Explain the internship. DSA- Stacks vs Queues. explain Binary Search, time complexity. Merge sort- nlogn divide and conquer. Recursion- Explain, base cases. Work Sample Questions Explain the aproach for the problem statement, Scopes of improvements for project Why Javascript, How can project can handle the multiple inputs, JAVA vs JS, any online tool that does the same job What is nosql, what does DB offer(ACID), why a web application, what is a web app which works on mobile- responsive. Individual contributions, any question(can we change the role), more question on stroage of files. code related question on async js,promises, settimeout, how to fix it, use of global array. optimization, performance, handling huge data, getting out the right data.

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