What will be the output of the program?

 class Test116 
 {  
 static final StringBuffer sb1 = new    
 StringBuffer(); 
 static final StringBuffer sb2 = new    
 StringBuffer(); 
 public static void main(String args[])    
 {
     new Thread()
     {     
         public void run()     
         {            
            synchronized(sb1)                
            {
               sb1.append("A");                  
               sb2.append("B");              
             }       
           }     
 }.start();     
 
  new Thread()   
  {       
      public void run()   
       {            
           synchronized(sb1)              
           {                  
              sb1.append("C");                  
              sb2.append("D");                
          }        
        }     
    }.start(); /* Line 28 */      
    
    System.out.println (sb1 + " " + sb2);       
    } 
 }