PropertyChangeSupport vs PropertyChangeListener in java

PropertyChangeSupport in java can be used in conjunction with PropertyChangeListener, and the bound property will notify all related listeners when the property value changes.

javaBean：

package com.wang.test.property;

import java.beans.PropertyChangeListener;
import java.beans.PropertyChangeSupport;

public class TestBean {

	protected final PropertyChangeSupport support = new PropertyChangeSupport(this);
	
	private String str;
	
	public String getStr() {
		return str;
	}

	public void setStr(String str) {
		support.firePropertyChange("str", this.str, str);
		this.str = str;
	}
	
	public void addPropertyChangeListener(PropertyChangeListener listener) {
		support.addPropertyChangeListener(listener);
	}
	
	public void removePropertyChangeListener(PropertyChangeListener listener) {
		support.removePropertyChangeListener(listener);
	}
}

 client：

package com.wang.test.property;

import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;

public class PropertyChangeSupportTest {

    public static void main(String[] args) {  
    	
        TestBean test = new TestBean();
        test.setStr("ddddd");
        test.addPropertyChangeListener(new PropertyChangeListener1());
        test.setStr("yyyy");
        
        //test.addPropertyChangeListener(new PropertyChangeListener2());
    	//test.setStr("hhhhhhf");
    }  
      
    public static class PropertyChangeListener1 implements PropertyChangeListener{

		@Override
		public void propertyChange(PropertyChangeEvent evt) {
			System.out.println( "1:  " + evt.getPropertyName() + "   " + evt.getNewValue() + "   " + evt.getOldValue());
			
		}
    }
    
    public static class PropertyChangeListener2 implements PropertyChangeListener{

		@Override
		public void propertyChange(PropertyChangeEvent evt) {
			System.out.println( "2:  " + evt.getPropertyName() + "   " + evt.getNewValue() + "   " + evt.getOldValue());
			
		}
    }
}