Threads Callback return value

I have a class extending another class (which immplements Runnable) and implements a CallBack. A value gets changed inside the Thread and I'd like to return it to the test() method. Is there a way to do this?

Code Snippet:

public class A extends B implements Callback{

    public void method1(){
        C c = new C(parameter1, parameter2, parameter3)
            Thread t = new Thread(cleanThread);
                t.start();  
    }

}

public class B implements Runnable{


}

public class C implements Runnable{
String parameter1;
boolean parameter2;
Hashtable parameter3;

public C(String parameter1,boolean parameter2,Hashtable parameter3){
this.parameter1= parameter1;
this.parameter2= parameter2;
this.parameter3= parameter3;
}
     public void run() {
    //do something and change parameter 2 and 3
    }
}

Now i want to return value of parameter2 and parameter3 to class A method1() function.

please advise how to do that.