Java Practice Programs

Java is a popular programming language that is used to develop a wide variety of applications. One of the best ways to learn Java is to practice writing programs. Many resources are available online and in libraries to help you find Java practice programs.

When practising Java programs, it is important to focus on understanding the concepts behind the code. Don't just copy and paste code from a website or book. Try to understand why the code is written the way it is. It will help you become a better Java programmer.

Java Basic Programs

1. Fibonacci series in Java
2. Factorial Program in Java
3. Palindrome Program in Java
4. How to reverse String in Java
5. How to Reverse a Number in Java
6. How do you find duplicate characters in a string
7. How to Print ASCII Value in Java
8. How to Create Object in Java
9. How to Compare Two Objects in Java
10. Program to swap two numbers
11. Java Program to Find Sum of Natural Numbers
12. Java Program to Display Odd Numbers From 1 to 100
13. Sum of Numbers in Java
14. Java Program to Find Largest of Three Numbers
15. Java Program to Check if a Given Number is Perfect Square
16. Java Program to Check if a Number is Positive or Negative

Java Number Programs

1. Special Number in Java
2. Perfect Number Program in Java
3. Prime Number Program in Java
4. Armstrong Number in Java
5. Lucky Number in Java
6. Spy Number in Java
7. Evil Number Java
8. Duck Number Java
9. ISBN Number Java
10. Krishnamurthy Number Java
11. Xylem and Phloem Number in Java
12. Kynea Numbers in Java
13. House Numbers in Java
14. Tribonacci Number Java
15. Odious Number in Java
16. Strontio Number in Java
17. Tech Number in Java
18. Fascinating Number in Java
19. Sunny Number in Java
20. Automorphic Number Program in Java
21. Mystery Number in Java
22. Lead Number in Java
23. Bouncy Number in Java
24. Economical Number in Java
25. Neon Number in Java
26. Unique Number in Java Program
27. Power of a Number in Java
28. Magic Number in Java
29. Catalan Number in Java
30. Self-Descriptive Numbers in Java
31. Hogben Numbers in Java
32. Centered Square Numbers in Java
33. Nude Numbers in Java
34. Sphenic Number in Java
35. Program to determine whether a given number is a happy number
36. Amicable Pair Number in Java
37. Achilles Number in Java
38. Frugal Number in Java
39. Cullen Number in Java
40. Smith Number in Java
41. Tetranacci Number in Java
42. Undulating Number in Java
43. Moran Numbers in Java
44. Cardinal Number in Java
45. Pyramidal Number in Java
46. Buzz Number Java
47. Bell Number in Java
48. Pancake Number in Java
49. Sublime Number in Java
50. Ramanujan Number or Taxicab Number in Java
51. Untouchable Number in Java
52. Pernicious Number in Java
53. Narcissistic Number in Java
54. Keith Number in Java
55. Goldbach Number in Java
56. Mersenne Number in Java
57. Adam Number in Java

Data structures

Java Array Programs

1. Java Program to sort the elements of an array in ascending order
2. Program to print the elements of an array
3. Program to print the elements of an array in reverse order
4. Program to print the largest element in an array
5. Program to print the duplicate elements of an array.
6. Character Array in Java
7. How to Take Array Input in Java
8. Program to print the smallest element in an array
9. Program to print the elements of an array
10. Java Program to right rotate the elements of an array
11. Java Program to print the sum of all the items of the array
12. Java Program to print Odd and Even Numbers from an Array
13. Java Program to remove duplicate element in an Array
14. Program to copy all elements of one array into another array
15. Jagged Array in Java
16. Minimum Difference Subarrays in Java
17. Beautiful Array in Java
18. Dynamic Array in Java
19. Iterate JSON Array Java
20. String Array in Java
21. Java ArrayList
22. How to Create Array of Objects in Java
23. Static Array in Java
24. Java Program to find Largest Number in an Array
25. Java Program to find Second Largest Number in an Array
26. Java Program to sort the elements of an array in descending order
27. Java Program to find Smallest Number in an Array
28. Java Program to find Third Largest Number in an Array
29. Program to print the duplicate elements of an array
30. Passing Array to Function In Java
31. Program to left rotate the elements of an array
32. Add elements to Array in Java
33. Program to print the sum of all the elements of an array
34. Java Program to find Second Smallest Number in an Array
35. Program to find the frequency of each element in the array
36. Program to print the elements of an array present on even position
37. Java Program to print the number of elements present in an array
38. Array Rotation in Java
39. Array Slicing in Java
40. How to Create a Mirror Image of A 2D Array in Java
41. Program to print the elements of an array present on odd position
42. Peak Index of Mountain Array Problem in Java
43. Plus One to Array Problem in Java
44. Zigzag Array in Java
45. Java Array Clone
46. Find unique elements in array Java
47. Java Program to Count the Occurrences of Each Character
48. Program to copy all the elements of one array into another array
49. Equilibrium Index of an Array in Java

Java Singly linked list Programs

1. Java Program to create and display a singly linked list
2. Java program to create a singly linked list of n nodes and count the number of nodes
3. Java Program to search an element in a singly linked list
4. Java program to insert a new node at the end of the singly linked list
5. Java program to insert a new node at the beginning of the singly linked list
6. Java program to create a singly linked list of n nodes and display it in reverse order
7. Java Program to insert a new node at the middle of the singly linked list
8. Program to sort the elements of the singly linked list
9. Java program to delete a node from the beginning of the singly linked list
10. Java program to remove duplicate elements from a singly linked list
11. Java program to delete a node from the end of the singly linked list
12. Java program to determine whether a singly linked list is the palindrome
13. Program to swap the last element of the singly linked list from the first one
14. Program to find the maximum and minimum value node from a singly linked list
15. Program to swap nodes in a singly linked list without swapping data
16. Insertion in singly linked list at beginning
17. Java program to delete a node from the middle of the singly linked list
18. Program to delete a new node from the beginning of the singly linked list
19. Program to search an element in a singly linked list
20. Searching in singly linked list
21. Deletion in singly linked list at beginning

Java Doubly Linked List Programs

1. Program to create and display a doubly linked list.
2. Java program to create a doubly linked list of n nodes and display it in reverse order
3. Java program to insert a new node at the end of the Doubly Linked List
4. Java program to insert a new node at the middle of the Doubly Linked List
5. Java program to sort the elements of the doubly linked list
6. Java program to delete a new node from the beginning of the doubly linked list
7. Java program to remove duplicate elements from a Doubly Linked List
8. Java program to search an element in a doubly linked list
9. Java program to rotate doubly linked list by N nodes
10. Java program to convert a given binary tree to doubly linked list
11. Program to insert a new node at the beginning of the doubly linked list.
12. Java program to delete a new node from the middle of the doubly linked list

Java Circular Linked List Programs

1. Program to create and display a circular linked list
2. Java program to sort the elements of the Circular Linked List
3. Java program to search an element in a Circular Linked List
4. Java program to create a Circular Linked List of N nodes and count the number of nodes
5. Java program to insert a new node at the end of the Circular Linked List
6. Java program to insert a new node at the middle of the Circular Linked List
7. Java program to insert a new node at the beginning of the Circular Linked List
8. Java program to delete a node from the beginning of the Circular Linked List
9. Java program to delete a node from the end of the Circular Linked List
10. Java program to delete a node from the middle of the Circular Linked List

Java Tree Programs

1. Java program to construct a Binary Search Tree and perform deletion and In-order traversal
2. Java program to implement Binary Tree using the Linked List
3. Java program to search a node in a Binary Tree
4. Java program to find the maximum depth or height of a tree
5. Java program to determine whether two trees are identical
6. Java program to find the sum of all the nodes of a binary tree
7. Java program to find the largest element in a Binary Tree
8. Program to search a node in a Binary Tree
9. Java program to create a doubly linked list from a ternary tree
10. Java program to find the smallest element in a tree
11. Segment Tree in Java
12. Level Order Traversal of a Binary Tree in Java
13. Morris Traversal for Inorder in Java
14. Tree traversal (Inorder, Preorder an Postorder)
15. Preorder Traversal
16. Inorder Traversal
17. Postorder Traversal
18. Binary Tree Traversal in Data Structure
19. Level Order Traversal of a Binary Tree in Java
20. Zigzag Traversal of a Binary Tree in Java
21. Vertical Order Traversal of a Binary Tree in Java
22. Morris Traversal for Inorder in Java
23. Morris Traversal for Preorder in Java
24. Level Order Traversal in Spiral form
25. Red Black Tree Java
26. Level order Traversal in a Binary Tree
27. Boundary Traversal of Binary tree

Java String Programs

1. Java Program to find all the permutations of a string
2. Java Program to separate the Individual Characters from a String
3. Java Program to find Reverse of the string
4. Java Program to count the total number of characters in a string
5. Java Program to find all subsets of a string
6. Java Program to determine whether one string is a rotation of another
7. Write a Java program to count the number of words in a string
8. Java Program to find maximum and minimum occurring character in a string
9. Java Program to toggle each word in String
10. Java Program to determine whether two strings are the anagram
11. Program to print smallest and biggest possible palindrome word in a given string
12. Java Program to swap two string variables without using third or temp variable
13. Java Program to remove all the white spaces from a string
14. Java Program to replace lower-case characters with upper-case and vice-versa
15. Java Program to count the total number of vowels and consonants in a string
16. Palindrome Partitioning Problem in Java
17. Isomorphic String in Java
18. Display Leaf nodes from Preorder of a BST in Java

Error and Exception Programs

1. Java throw Exception
2. Java Custom Exception
3. Arithmetic Exception in Java
4. Exception Class in Java
5. InputMismatchException in Java
6. Java Exception Propagation
7. Java try-catch block
8. customized exception in Java
9. Java finally block
10. How to avoid null pointer exception in Java
11. ConcurrentModificationException in Java
12. FileNotFoundException in Java
13. Different Ways to Print Exception Message in Java
14. How to resolve IllegalStateException in Java
15. Exception Handling with Method Overriding in Java
16. Java 7 Catch Multiple Exceptions
17. NoClassDefFoundError in Java
18. ClassCast Exception in Java
19. Java Console Error
20. Identifier Expected Error in Java
21. Java Catch Multiple Exceptions
22. lang.NoSuchMethodError
23. Chained Exceptions in Java
24. StringIndexOutOfBoundsException in Java
25. NZEC in Java
26. NoSuchElementException in Java
27. Exception in Thread Main java.util.NoSuchElementException no line Found
28. How to Create Test Cases for Exceptions in Java

Class and Interface Programs

1. How to Create Singleton Class in Java
2. Types of Classes in Java
3. Marker Interface in Java
4. ByteStream Classes in Java
5. Dictionary Class in Java
6. Abstract class in Java
7. Wrapper classes in Java
8. Java Inner Classes (Nested Classes)
9. Java Math class
10. Java StringBuffer Class
11. Java Scanner
12. Java static nested class
13. Java FileInputStream Class
14. Java FileReader Class
15. Java Member Inner class
16. Java Console Class
17. How to create Immutable class
18. Exception Class in Java
19. Sealed Class in Java
20. Why We Use Static Class in Java
21. Singleton Class in Java
22. Java Nested Interface
23. Java Functional Interfaces
24. Java Comparable interface
25. Iterator in Java
26. Java Runnable Interface
27. Marker Interface in Java
28. Servlet Interface
29. Java 9 Private Interface Methods
30. Java Predicate Interface
31. Java Consumer Interface
32. Lock Interface in Java
33. TypeScript Interface
34. if Condition in Lambda Expression Java
35. How to Mock Lambda Expression in Java
36. How to Return Value from Lambda Expression Java
37. AWS Lambda in Java

Java Matrix Programs

1. Java Program to add two matrices
2. Java Program to transpose matrix
3. Java Program to multiply two matrices
4. Java Program to display the lower triangular matrix
5. Java Program to find the sum of each row and each column of a matrix
6. Java Program to determine whether a given matrix is an identity matrix
7. Java Program to display the upper triangular matrix
8. Java Program to determine whether a given matrix is a sparse matrix
9. Rotate Matrix by 90 Degrees in Java | Rotate Matrix in Java Clockwise and Anti-clockwise
10. Normal and Trace of a Matrix in Java
11. Java Program to Print Matrix in Z Form
12. Set Matrix Zeros in Java
13. Find Saddle Point of a Matrix in Java
14. Print Matrix Diagonally in Java
15. Rotate A Matrix By 180 Degree in Java
16. Find Saddle Point of a Matrix in Java
17. Program to print the elements of an array in reverse order
18. Set Matrix Zeros in Java
19. Java Program to subtract the two matrices

Java Pattern programs

1. Alphabet Pattern in Java
2. Ladder Pattern in Java
3. Fish Pattern in Java
4. Zig Zag Star and Number Pattern in Java
5. Heart Pattern in Java
6. Butterfly Pattern in Java
7. Crown Pattern in Java
8. Swastika Pattern in Java
9. Christmas Tree Pattern in Java
10. Java Program to Print Spiral Pattern
11. Print Pencil Shape Pattern in Java

Java Conversion Programs

1. Java Convert String to int
2. Java Convert int to String
3. Java Convert Binary to Decimal
4. Java Convert int to char
5. Java Convert Decimal to Binary
6. Java Convert long to int
7. Java long to String
8. Convert Roman to Integer in Java
9. Java Convert int to long
10. Java Convert String to double
11. Java Convert String to char
12. Java Binary to Hexadecimal Conversion
13. Java Convert Decimal to Octal
14. Java String to Date
15. Java Convert char to String
16. Convert Integer to Roman Numerals in Java
17. Convert IP to Binary in Java
18. Program to convert Celsius into Fahrenheit
19. Program to convert Fahrenheit into Celsius
20. Java Convert int to double
21. Java Convert Octal to Decimal
22. Program to convert hours into minutes and seconds
23. Program to Convert m to Feet and Inches
24. Program to Convert Inches to cm
25. Program to Convert cm to Feet and Inches
26. Java Program Number to Word
27. Java Convert Decimal to Hexadecimal
28. Program to Convert Inches to meter
29. Program to Convert Meter to Centimeter
30. Java Convert boolean to String
31. Program to Convert Feet to cm
32. Program to Convert mm to cm
33. Program to Convert millimeter to Feet
34. Program to Convert Feet to m
35. Java Convert char to int
36. Java Convert double to int
37. Program to Convert Feet to Inches
38. Program to convert temperature degree from Celsius to Kelvin
39. Java String to float
40. How to convert byte array to String in Java
41. Java Convert String to boolean
42. Program to Convert Inches to Feet
43. Java Hexadecimal to Binary Conversion
44. Java Convert double to String
45. How to convert String to String array in Java

Java Game Programs

1. Tetris Game in Java
2. Stone Game in Java
3. Sudoku in Java
4. FizzBuzz Program in Java
5. Puzzle Game in Java
6. Example of Pic Puzzle Game
7. Tic Tac Toe Game in Java

File Handling programs

1. How to Create a File in Java
2. How to delete a file in Java
3. How to Read CSV File in Java
4. Java FileWriter Class
5. Java File Extension
6. Java FileReader Class
7. How to Read Excel File in Java
8. Java Program to find the number of the words in the given text file
9. Java FileInputStream Class
10. Copy Content/ Data From One File to Another in Java
11. Java Get File Size
12. Java Program to find the most repeated word in a text file
13. Java - RandomAccessFile
14. How to read file line by line in Java
15. Read PDF File in Java
16. How to Create Zip File in Java
17. Java Program to find the most repeated word in a text file
18. How to make an executable jar file in Java
19. Java File Upload to a Folder
20. Java Create Jar Files
21. List All Files in a Directory in Java
22. Zipping and Unzipping Files in Java
23. Java SFTP | File Transfer Using SFTP in Java JSCH
24. Example to retrieve file from Oracle database