More about methods in Java using NetBeans IDE

This section explains the code listed in the previous section. Let us start with the following:

    int x=0;
    int y=0;
    int z=0;

Now, you can observe that I declared three fields/attributes for the class “MyCalc.” What follows is the new “method” I introduced:

    public void calcSum() {
        z = x + y;
    }

The above method is named “calcSum” and it returns a “void” type. The “void” indeed is simply “nothing.”  In other words, the method “calcSum” (unlike our previous “getSum” method) doesn’t return any value after its calculation.

Now, if we proceed to our “test” frame, we have the following initially:

        MyCalc obj1 = new MyCalc();
        obj1.x = 10;
        obj1.y = 20;
        obj1.calcSum();

I declared an object named “obj1.”  Now, it internally contains four members (x, y, z, calcSum). You can also observe that I am simply providing the values for “x” and “y” (but not “z”). After assigning the values to “x” and “y,” I am simply calling “calcSum.”  This method will indeed calculate the sum of “x” and “y” and place the result in “z” (which is also a member to the same object “obj1”).

You must also observe that I am not taking (or assigning) any value from “calcSum,” as it doesn’t return anything at this moment. Similarly, I am also working with another object as following:

        MyCalc obj2 = new MyCalc();
        obj2.x = 100;
        obj2.y = 200;
        obj2.calcSum();

Once the calculations are over, I display the values of “z” in each of those objects with the following two statements:

        this.lblMsg.setText("Sum = " + String.valueOf(obj1.z));
        this.lblMsg2.setText("Sum = " + String.valueOf(obj2.z));