Java Static Program

class StaticBlock {
  public static void main(String[] args) {
    System.out.println("Main method is executed.");
  }

  static {
    System.out.println("Static block is executed before main method.");
  }
}

class Languages {
  public static void main(String[] args) {
    display();
  }

  static void display() {
    System.out.println("Java is my favorite programming language.");
  }
}

Java String Methods

class StringMethods
{
  public static void main(String args[])
  {
    int n;
    String s = "Java programming", t = "", u = "";

    System.out.println(s);

    // Find length of string

    n = s.length();
    System.out.println("Number of characters = " + n);

    // Replace characters in string

    t = s.replace("Java", "C++");
    System.out.println(s);
    System.out.println(t);

    // Concatenating string with another string

    u = s.concat(" is fun");
    System.out.println(s);
    System.out.println(u);
  }
}

Java Methods

class Methods {

  // Constructor method

  Methods() {
    System.out.println("Constructor method is called when an object of it's class is created");
  }

  // Main method where program execution begins

  public static void main(String[] args) {
    staticMethod();
    Methods object = new Methods();
    object.nonStaticMethod();
  }

  // Static method

  static void staticMethod() {
    System.out.println("Static method can be called without creating object");
  }

  // Non static method

  void nonStaticMethod() {
    System.out.println("Non static method must be called by creating an object");
  }
}

Java Program To Convert Fahrenheit To Celsius

import java.util.*;

class FahrenheitToCelsius {
  public static void main(String[] args) {
    float temperatue;
    Scanner in = new Scanner(System.in);     

    System.out.println("Enter temperatue in Fahrenheit");
    temperatue = in.nextInt();

    temperatue = ((temperatue - 32)*5)/9;

    System.out.println("Temperatue in Celsius = " + temperatue);
  }
}

Java Program To Find Odd Or Even

import java.util.Scanner;

class OddOrEven
{
   public static void main(String args[])
   {
      int x;
      System.out.println("Enter an integer to check if it is odd or even ");
      Scanner in = new Scanner(System.in);
      x = in.nextInt();

      if ( x % 2 == 0 )
         System.out.println("You entered an even number.");
      else
         System.out.println("You entered an odd number.");
   }
}

Java Program To Add Two Numbers

import java.util.Scanner;

class AddNumbers
{
   public static void main(String args[])
   {
      int x, y, z;
      System.out.println("Enter two integers to calculate their sum ");
      Scanner in = new Scanner(System.in);
      x = in.nextInt();
      y = in.nextInt();
      z = x + y;
      System.out.println("Sum of entered integers = "+z);
   }
}

 

Above code can add only numbers in range of integers(4 bytes), if you wish to add very large numbers then you can use BigInteger class. Code to add very large numbers:

import java.util.Scanner;
import java.math.BigInteger;

class AddingLargeNumbers {
  public static void main(String[] args) {
    String number1, number2;
    Scanner in = new Scanner(System.in);

    System.out.println("Enter first large number");
    number1 = in.nextLine();

    System.out.println("Enter second large number");
    number2 = in.nextLine();

    BigInteger first  = new BigInteger(number1);
    BigInteger second = new BigInteger(number2);
    BigInteger sum;

    sum = first.add(second);

    System.out.println("Result of addition = " + sum);
  }
}

Output of program:

Enter first large number
11111111111111
Enter second large number
99999999999999
Result of addition = 111111111111110

How To Get Input From User In Java

import java.util.Scanner;

class GetInputFromUser
{
   public static void main(String args[])
   {
      int a;
      float b;
      String s;

      Scanner in = new Scanner(System.in);

      System.out.println("Enter a string");
      s = in.nextLine();
      System.out.println("You entered string "+s);

      System.out.println("Enter an integer");
      a = in.nextInt();
      System.out.println("You entered integer "+a);

      System.out.println("Enter a float");
      b = in.nextFloat();
      System.out.println("You entered float "+b);  
   }
}