Object as a parameter?

Question

I had asked a question about implementing a class by subclass in Java previously and I found a different approach used.(different for me!) URL: here

public void paintComponent(Graphics g){

this line was confusing for me, for a class was passed as a parameter. Well, I thought of giving a try and understand before I asked here. Here's my code:

public class parameterObject{

String name;
int age;

public parameterObject(){}
public parameterObject(String inputName,int inputAge){

    name = inputName;
    age = inputAge;

}
public void testObject(){

System.out.println(name);
System.out.println(age);
}

}

and in the next class, I used a method to pass parameterObject as a parameter (in bjueJ environment)

public void testFunction(parameterObject pO, int a){
 pO.testObject();
}

when I called the method, testFunction(...)It asked for parameter values and I entered "arpan",19 and 20. error: expected.. and then I tried using null for the objectParameter and then the JVM threw nullPointException error.. what was supposed to happen and what is lacking in my understanding? please help.

No class is being passed as a parameter. An instance of Graphics is being passed as a parameter. Your problem is obscure and your question unclear. — user207421, Apr 15 '14 at 00:59

score 0 · Answer 1 · answered Apr 15 '14 at 00:59

0

if i understand what you did , i think you did like that:

X.testFunction("arpan", 19, 20);

which is not right, u have to do like this:

X.testFunction(new parameterObject("arpan", 19), 20);

answered Apr 15 '14 at 00:59

Mouad EL Fakir

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if you need more explanation just ask! – Mouad EL Fakir Apr 15 '14 at 01:00
Here is the screenshoot of what happened to the function when I ran it: https://www.dropbox.com/s/vnnnfq61m17z5li/Screenshot%20from%202014-04-15%2010%3A43%3A36.png – user3519322 Apr 15 '14 at 02:31

score 0 · Answer 2 · answered Apr 15 '14 at 01:02

If I understand correctly testFunction expects two parameters: First p0 of type parameterObject and then a of type int.

Did you call the method like this: testFunction("arpan", 19, 20)?

This call wouldn't "match the method signature". That means the types of the values you passed in don't match with those the method expects. "arpan" is a String and 19, 20 are two int.

You could do something like this instead:

parameterObject abc = new parameterObject("arpan", 19);
testFunction(abc, 17);  // one parameterObject and one int - just like testFunction expects

Object as a parameter?

2 Answers2