Java Programs for Practice

// Basic Java Structure
public class Main {
    public static void main(String[] args) {
        System.out.println("Practice Java Programs");
    }
}

// 1. Print Hello World
class HelloWorld {
  public static void main(String[] args) {
    System.out.println("Hello World");
  }
}


// 2. Swap two numbers
class SwapNumbers {
  public static void main(String[] args) {
    int a = 10, b = 20;

    int temp = a;
    a = b;
    b = temp;

    System.out.println("a=" + a + " b=" + b);
  }
}


// 3. Check Even or Odd
class EvenOdd {
  public static void main(String[] args) {
    int num = 7;

    if (num % 2 == 0) {
      System.out.println("Even");
    } else {
      System.out.println("Odd");
    }
  }
}


// 4. Print Multiplication Table
class MultiplicationTable {
  public static void main(String[] args) {
    int num = 5;

    for (int i = 1; i <= 10; i++) {
      System.out.println(num + " x " + i + " = " + (num * i));
    }
  }
}


// 5. Sum of Digits
class SumOfDigits {
  public static void main(String[] args) {
    int num = 1234;
    int sum = 0;

    while (num > 0) {
      sum += num % 10;
      num /= 10;
    }

    System.out.println(sum);
  }
}


// 6. Reverse Number
class ReverseNumber {
  public static void main(String[] args) {
    int num = 1234;
    int rev = 0;

    while (num > 0) {
      rev = rev * 10 + (num % 10);
      num /= 10;
    }

    System.out.println(rev);
  }
}


// 7. Print Star Pattern
class StarPattern {
  public static void main(String[] args) {
    for (int i = 1; i <= 5; i++) {
      for (int j = 1; j <= i; j++) {
        System.out.print("*");
      }
      System.out.println();
    }
  }
}

• 1 Improve logic building
• 2 Prepare for interviews
• 3 Understand syntax
• 4 Build confidence in coding

• 1 Basic programs
• 2 Loop programs
• 3 Array programs
• 4 Pattern programs

• 1 Loops and conditions
• 2 Strings and arrays
• 3 Math problems
• 4 Patterns

• 1 Start with basics
• 2 Repeat daily practice
• 3 Solve interview questions
• 4 Increase difficulty gradually