I don't know how to díplay < string + addelement(x) > in jlist

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Java

Thtread A creates a random number and add to the text area A, then notify the thread B. The thread B then add this number to the text area B and notify the thread A to create a new random number,… and continue like that.

Example:

Thread A Thread B
A create 51 B display 51
A create 43 B display 43
A create 29

My problem: My program ran successfully with numbers but I don't know how to display "A create + number" and "B display + number" like example.

What I have tried:

DefaultListModel ta,tb;
    Thread a, b; Random u;
    public JFrame1() {
        initComponents();
        ta = new DefaultListModel();
        text1.setModel(ta);
        tb = new DefaultListModel();
        text2.setModel(tb);
        u = new Random();
        initThreadA();
        initThreadB();
    }
    
void threadA_work() {
    String []ar = {"A create %d"};
       int x = u.nextInt(100);
       //ta.addElement("A create ");
       ta.addElement(x);
    }
    void threadB_work() {
        int size = ta.getSize();
        int x = (Integer) ta.elementAt(size - 1);
        //tb.addElement("B display ");
        tb.addElement(x);
    }

    void initThreadA() {
        a = new Thread() {
            public void run() {
                while(true) {
                    threadA_work();
                    try {
                        sleep(1000);
                    } catch(InterruptedException e) { } 
                    synchronized(b) {
                        b.notify();
                    }
                    try {
                        synchronized(this) {
                            wait();
                        } 
                    } catch(InterruptedException e) { }
                }    
            }  
        };  
    }

    void initThreadB() {
        b = new Thread() {
            public void run() {
                while(true) {
                    try {
                        synchronized(this) {
                            wait();
                        } 
                    } catch(InterruptedException e) { }
                    threadB_work();
                    try {
                        
                        sleep(1000);
                    } catch(InterruptedException e) {  }
                    synchronized(a) {
                        a.notify(); 
                    }
                }    
           }  
        };  
    }
    private void bt1ActionPerformed(java.awt.event.ActionEvent evt) {                                    
        a.start();
        b.start();  
    }