This post contains a java code that adds two input entered by the user and show the result. 
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import java.awt.JobAttributes;
import javax.swing.JOptionPane;
public class Addition {
 
 
 public static void main(String args[]) {
  
  String number1, number2; 
  Integer num1,num2,sum; 
  
  number1 = JOptionPane.showInputDialog("Enter first number:");
  number2 = JOptionPane.showInputDialog("Enter second number:");
  
  num1 = Integer.parseInt(number1);
  num2 = Integer.parseInt(number2);
  
  sum = num1 + num2; 
  
  
  JOptionPane.showMessageDialog(null, "The sum is "+sum,"Results",JOptionPane.INFORMATION_MESSAGE);
     
 }
}
