How to get Refrence of the calling Object in the called method

Question

Is there any way to achive below without having explicitly passing or storing a's refrence.??
class A {
public void run(){
B b= new B();
b.doStuff();
public static void main(String [] args){
A a = new A();
a.run();
class B {
public void doStuff(){
/* ??????????? Is it possible to get Instance of A, a's refrence without changing doStuff() signature */
If not, how does the following join() method of Thread gets the refrence of the Instance of Calling Instance(t1 & t2) , so as to attach the calling Thread at the end of called Thread(t) ??
class TestThread extends Thread{
public void run(){
for (int i=0; i < 10; i++)
     System.out.println("Iteration:"+i+" of TestThread");
class A extends Thread{
Thread t;
public A(Thread t){
this.t=t;
public void run(){
try {
t.join();
}catch (InterruptedException e){}
for (int i=0; i < 10; i++)
     System.out.println("Iteration:"+i+" of A Instance"+this);
public class Main{
public static void main(String [] args) {
TestThread t = new TestThread();
A t1 = new A(t);
A t2 = new A(t);
t1.start();
t2.start();
t.start();
}

Answer 1

Reposting with markup.
class A {
    public void run(){
        B b= new B();
        b.doStuff();
    public static void main(String [] args){
        A a = new A();
        a.run();
class B {
    public void doStuff(){
         * ??????????? Is it possible to get Instance of A, a's
         * refrence without changing doStuff() signature
}If not, how does the following join() method of Thread gets the refrence of the Instance of Calling Instance(t1 & t2) , so as to attach the calling Thread at the end of called Thread(t) ??
class TestThread extends Thread{
    public void run(){
        for (int i=0; i < 10; i++) System.out.println("Iteration:"i" of TestThread");
class A extends Thread{
    Thread t;
    public A(Thread t){
        this.t=t;
    public void run(){
        try {
            t.join();
        }catch (InterruptedException e){}
        for (int i=0; i < 10; i++) System.out.println("Iteration:"i" of A Instance"+this);
public class Main{
    public static void main(String [] args) {
        TestThread t = new TestThread();
        A t1 = new A(t);
        A t2 = new A(t);
        t1.start();
        t2.start();
        t.start();
}