ABTest.java

import java.util.HashSet;

public class ABTest {
	private HashSet<String> very_priv = new HashSet<String>(10);
	
	
	public static void main(String[] args) {
		ABTest a = new ABTest();
		ABTest b = new ABTest();
		
		a.addToPrivate("Shit");
		b.addToPrivate("Nope");
		
		System.out.println(a.getRepr());
		System.out.println(b.getRepr());
		
	}
	
	public void addToPrivate(String s) {
		very_priv.add(s);
	}
	
	public String getRepr(){
		return very_priv.toString(); 
	}
	

}

gistfile1.txt

$ java ABTest
[Shit]
[Nope]