use of integer in java

public class first
{
public static void main(String args[])
{
int a = 10;
int b = 30;
System.out.println("Addition of A And B =" +(a+b));
System.out.println("Subtraction of A And B =" +(a-b));
System.out.println("Division of a and b ="+(a/b));
System.out.println("Multiplication of a and b =" +(a*b));
}
}