Interview Questions Java Collection This Java exercise collection is designed to deepen your understanding of Java and refine your coding skills. The programs provide hands-on experience in solving real-world problems, reinforce key concepts, and help you master Java fundamentals, including variables, control statements, arrays, strings, methods, and object-oriented programming. Covers Java practice problems from beginner to advanced levels. Helps strengthen Java programming and problem-solving skills. Includes programs based on numbers, patterns, arrays, and strings. Java Beginner Exercises These exercises focus on basic Java syntax, arithmetic operations, numbers, patterns, arrays, and simple string operations. 1. Write a Hello World Program in Java Input: Hello World! Output: Hello World! Click Here for the Solution 2. Write a Program in Java to Add two Numbers. Input: 2 3 Output: 5 Click Here for the Solution 3. Write a Program to Swap Two Numbers Input: a=2 b=5 Output: a=5 b=2 Click Here for the Solution 4. Write a Java Program to convert Integer numbers and Binary numbers. Input: 9 Output: 1001 Click Here for the Solution 5. Write a Program to Find Factorial of a Number in Java. Input: 5 Output: 120 Click Here for the Solution 6. Write a Java Program to Add two Complex Numbers. Input: 1+2i 4+5i Output: 5+7i Click Here for the Solution 7. Write a Program to Calculate Simple Interest in Java Input : P = 10000 R = 5 T = 5 Output : 2500 Click Here for the Solution 8. Write a Program to Find Sum of Fibonacci Series Number Input: n = 4 Output: 33 Explaination: Sum of numbers at even indexes = 0 + 1 + 3 + 8 + 21 = 33. Click Here for the Solution Java Exercise on Pattern 9. Write a Program to Print the Pascal's Triangle in Java Click Here for the Solution 10. Write a Program to Print Pyramid Number Pattern in Java. Click Here for the Solution 11. Write a Java Program to Print Pattern. Click Here for the Solution 12. Write a Java Program to Print Pattern. Click Here for the Solution 13. Java Program to Print Patterns. Input: number = 7 Click Here for the Solution Java Intermediate Exercises These exercises require more understanding of arrays, strings, searching techniques, and common algorithms. 14. Write a Java Program to Compute the Sum of Array Elements. Input: [ 2, 4, 6, 7, 9] Output: 28 Click Here for the Solution 15. Write a Java Program to Find the Largest Element in Array Input: [ 7, 2, 5, 1, 4] Output: 7 Click Here for the Solution 16. Write Java Program to Find the Tranpose of Matrix Click Here for the Solution 17. Java Array Program For Array Rotation Input: arr[] = {1, 2, 3, 4, 5, 6, 7}, d = 2 Output: 3 4 5 6 7 1 2 Explaination: d=2 so 2 elements are rotated to the end of the array. So, 1 2 is rotated back So, Final result: 3, 4, 5, 6, 7, 1, 2 Click Here for the Solution 18. Java Array Program to Remove Duplicate Elements From an Array Input: [ 1, 2, 2, 3, 3, 3, 4, 5 ] Output: [ 1, 2, 3, 4, 5 ] Click Here for the Solution 19. Java Array Program to Remove All Occurrences of an Element in an Array Input: array = [ 1, 2, 1, 3, 5, 1 ] , key = 1 Output: [2, 3, 5] Explaination: all the occurrences of element 1 is removed from the array So, array becomes from [ 1, 2, 1, 3, 5, 1 ] to Final result: [2, 3, 5] Click Here for the Solution String Exercises in Java 20. Java program to check whether a string is a Palindrome Input: "racecar" Output: Yes Explaination: As racerar after reversing becomes racecar. As Reverse of String is same as String so it is Palindrome Click Here for the Solution

21. Java String Program to Check Anagram Input: str1 = "Silent" str2 ="Listen" Output: Strings are Anagram Explaination: As all the elements in str1 are exact same as to create str2 . i.e., we can create str2 using elements of str1 without removing any element or removing any extra element. Click Here for the Solution 22. Java String Program to Reverse a String Input: str= "Geeks" Output: "skeeG" Click Here for the Solution 23. Java String Program to Remove leading zeros Click Here for the Solution Java Advanced Searching and Sorting Exercises These exercises involve fundamental searching and sorting algorithms and require a stronger understanding of algorithmic problem-solving. 24. Write a Java Program for Linear Search. Time Complexity: O(N) Space Complexity: O(N) Click Here for the Solution 25. Write a Binary Search Program in Java. Time Complexity: O(logN) Space Complexity: O(N) Click Here for the Solution Practice Problems in Java Sorting Algorithms 26. Java Program for Bubble Sort. Time Complexity: O(N 2 ) Space Complexity: O(1) Click Here for the Solution 27. Write a Program for Insertion Sort in Java. Time Complexity: O(N 2 ) Space Complexity: O(1) Click Here for the Solution 28. Java Program for Selection Sort. Time Complexity: O(N 2 ) Space Complexity: O(1) Click Here for the Solution 29. Java Program for Merge Sort. Time Complexity: O(N logN) Space Complexity: O(N) Click Here for the Solution 30. Java Program for QuickSort. Time Complexity: O(N logN) Space Complexity: O(1) Click Here for the Solution Introduction 4 min read Variables 2 min read Data Types 7 min read Operators 7 min read Decision Making 5 min read Methods 7 min read Arrays 7 min read Strings 5 min read Introduction 6 min read Constructors 6 min read Encapsulation 3 min read Inheritance 8 min read Polymorphism 5 min read Abstraction 5 min read Interfaces 8 min read Collection class 9 min read Collection Interface 5 min read List Interface 8 min read Set Interface 5 min read Queue Interface 5 min read Map Interface in Java 6 min read Iterator 4 min read Exception handling 6 min read Java Multithreading Tutorial 3 min read Synchronization in Java 8 min read File handling 6 min read Method References 3 min read Java 8 Stream Tutorial 8 min read Memory Management 4 min read Garbage Collection in Java 6 min read Networking 6 min read JDBC 5 min read Interview Questions 15+ min read Programs 6 min read Practice Problems 5 min read Quiz 1 min read Project Ideas 15+ min read Java Backend Course 2 min read Placement 360 Course 2 min read