Top 40 Java Interview Coding Questions 2019

java interview coding questions

Please do read our previous post on SQL queries interview questions, if you haven’t read it first.

In this post, we have listed some of the most common java interview coding questions. Hope you find these useful.

List of java interview coding questions for 2019

  1. Write a program to reverse a string using a recursive algorithm.
  2. Write a program to reverse a number.
  3. Find the longest substring without repeating characters.
  4. Write a program to find sum of each digit in the given number using recursion.
  5. Write a program to check the given number is a prime number or not?
  6. Write a program to remove duplicates from a sorted array.
  7. Write a program to check the given number is a binary number or not?
  8. How to check the given Binary Tree is Binary Search Tree (BST) or not?
  9. Find min and max value from Binary Search Tree (BST)
  10. Find out a duplicate number between 1 to N numbers.
  11. Write a program to find maximum repeated words from a file.
  12. Implement Binary Search Tree (BST) post-order traversal (depth-first).
  13. Write a program for Bubble Sort in java.
  14. Write a program to convert binary to a decimal number.
  15. Write a program to find out duplicate characters in a string.
  16. Write a program to convert a string to a number without using Integer.parseInt() method.
  17. Write a program to sort a map by value.
  18. Write a program to find the given number is Armstrong number or not?
  19. Implement Binary Search Tree (BST) pre-order traversal (depth-first).
  20. Write a program to get a distinct word list from the given file.
  21. Write a program to print fibonacci series.
  22. Write a program to implement ArrayList.
  23. Write a program to convert a decimal number to binary format.
  24. Write a program to find the top two maximum numbers in an array.
  25. Find the height of a Binary Search Tree (BST)
  26. Write a program for Insertion Sort in java.
  27. How to delete a node from Binary Search Tree (BST)?
  28. How to reverse the Singly Linked List?
  29. Implement Binary Search Tree (BST)
  30. Write a program to find the sum of the first 1000 prime numbers.
  31. How to sort a Stack using a temporary Stack?
  32. Write a program to find two lines with max characters in descending order.
  33. How to get distinct elements from an array by avoiding duplicate elements?
  34. Write a program to implement hashcode and equals.
  35. Write a program to create a deadlock between two threads.
  36. Find out middle index where the sum of both ends is equal.
  37. Write a program to print all permutations of a given string.
  38. Write a program to get a line with max word count from the given file.
  39. Implement Binary Search Tree (BST) Level order traversal (breadth-first).
  40. Implement Binary Search Tree (BST) in-order traversal (depth-first).

Please do comment for more interview questions which you faced practically. We will include in the above list.

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