This blog posts shows how to add two numbers in Java:

public class Demo {

    public static void main(String args[]){ 
        int a = 10; 
        int b = 20; 
        int result = add(a,b); 
        System.out.println("Result is "+result); 
    }

    private static int add(int a,int b){ 
        int result = a+b; 
        return result; 
    } 
}

Here, we are using the method add to add two numbers. It accepts 2 integer values, adds them and returns the result. You can change the data type/ return value to anything else like long,short, float, double, etc.

If you run the code, the following output will get printed to the console:

 

Result is 30