how to change an instance variable of an object from multiple arraylist references?

[smande3]

I can not figure out why i dont get the output when i compile and run

1
2
3

Instead i get

0
0
0

I'm trying to figure out how to build an array list of objects than build a sub-arraylist off of that one and be able to use the reference on either array to edit one of the objects instance variables.

so i made this as a very basic example as a way to test before i wrote all the code and i cant even get the output to be correct for the first system.out.println which is basically using a getter setter method.

Im new to java and im sure its a very basic rookie mistake that once pointed out ill understand but i see no issue in my code here it is.

1. Test Class is supposed to make Test objects that have the instance variable testIndex

public class Test {
	
	int testIndex;

	public Test() {
		testIndex = 0;	
		}
	
	public void incrementTestIndex() {
		testIndex = testIndex++;
		}
	
	public int getTestIndex() {
		return testIndex;
		}
	}

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2. This is the primary ArrayList which only has 1 element added for simplicity of my question

import java.util.ArrayList;

public class Primary {

ArrayList<Test> primary;
	
	public Primary() {
		primary = new ArrayList<Test>();
		}

	public void addTestToPrimary(Test a) {
		primary.add(a);
		}
	
	public Test getTest(int a) {
		Test primaryTest = primary.get(a);
		return primaryTest;
		}
}

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3. this is supposed to hold the Test object passed from the primary ArrayList

import java.util.ArrayList;

public class Pass {
	
ArrayList<Test> pass;

public Pass() {
	pass = new ArrayList<Test>();
	}
public void addTestToPass(Test a) {
	pass.add(a);
	}
public Test getTest(int a) {
	Test passTest = pass.get(a);
	return passTest;
	}

}

-----------------------------------------------------------------

4. here is the main method it should first

import java.util.ArrayList;

public class Main {

	public static void main (String[] args) {
		Test test = new Test();
		test.incrementTestIndex();
		System.out.println(test.getTestIndex());
		Primary primaryReference = new Primary();
		primaryReference.addTestToPrimary(test);
		primaryReference.getTest(0).incrementTestIndex();
		System.out.println(test.getTestIndex());
		Pass passReference = new Pass();
		passReference.addTestToPass(primaryReference.getTest(0));
		passReference.getTest(0).incrementTestIndex();
		System.out.println(test.getTestIndex());
		
	}
}

I need each arraylist in Primary and Passed to be in there own class for when i make the actual application im trying to do what it actually is would be a texas hold em app. one array list for players at the table and a secondary list for players still in the hand...

I need to be able to take all the players info from its player object pass it to Table ArrayList than pass it from table to active in hand.

Please Help!

[JosAH]

Carefully check line #10 in your first class again:

testIndex = testIndex++;

It doesn't do what you think it does ...

kind regards,

Jos