Synchronized: Summary of thread synchronization method usage

Synchronized
1. Multi-threaded execution of the same object synchronized function, thread synchronization is correct;

The instance code is as follows:
public class Test1 implements runnable{

Defining the same object

Static TEST2 action;
 
 public static void Main (string[] args) {
  //TODO auto-generated method Stub
  
  class cls;
  try {
   cls = Class.forName ("Test2");
      action = (Test2) cls.newinstance ();
   test1 t1 = new Test1 ();
   for (int i=0;i<1;i++) {
    new Thread (T1). Start ();
    new Thread (T1). Start ();
    new Thread (T1). Start ();
    new Thread (T1). Start ();
   }
  } catch (Exception e) {
   //TODO auto-generated catch block
    E.printstacktrace ();
  }
 }

public void Run () {
TODO auto-generated Method Stub
try {
Action.getrandomstring ();
} catch (Exception e) {
TODO auto-generated Catch block
E.printstacktrace ();
}
}
}

public class Test2 {

public static void Main (string[] args) {

}
Call the synchronized function of the same object without adding STATCI adornments
Public synchronized void Getrandomstring () throws Interruptedexception {
System.out.println ("$$$$$$$$$$$$$$$$$$");
Thread.Sleep (1000);
Random random = new random ();
int aa = Random.nextint (10);
int bb = Random.nextint (10);
int cc = Random.nextint (10);
System.out.println (string.valueof (aa) +string.valueof (BB) +string.valueof (cc));
System.out.println ("############");
}
}
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2. Multi-threaded execution of different object synchronized function, thread synchronization error;

The instance code is as follows:
public class Test1 implements runnable{

 public static void Main (string[] args) {
  try {
   test1 t1 = new Test1 ();
   for (int i=0;i<100;i++) {
    new Thread (T1). Start ();
    new Thread (T1). Start ();
    new Thread (T1). Start ();
    new Thread (T1). Start ();
   }
  } catch (Exception e) {
   //TODO auto-generated catch block
    E.printstacktrace ();
  }
 }

public void Run () {
TODO auto-generated Method Stub
Class CLS;
try {
CLS = Class.forName ("Test2");
Test2 action = (Test2) cls.newinstance ();
Action.getrandomstring ();
} catch (Exception e) {
TODO auto-generated Catch block
E.printstacktrace ();
}
}
}

public class Test2 {

public static void Main (string[] args) {

 }
 
 /**
  * @param args
  * @throws interruptedexception
  */
 // Call the synchronized function of different object, need to add statci adornment, otherwise thread synchronization fails
 public  synchronized  void getrandomstring () throws interruptedexception {
  system.out.println ("$$$$$$$$$$$$$$$$$$");
  thread.sleep (1000);
  random random = new Random ();  
        int aa = Random.nextint (10);
        int bb = random.nextint (10);
        int cc = Random.nextint (10);
  system.out.println (string.valueof (aa) +string.valueof (BB) +string.valueof (cc));
  system.out.println ("############");
 }
}
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   3. Multithreaded execution of synchronized static functions of different objects, thread synchronization is correct;

The instance code is as follows:
public class Test1 implements runnable{

public static void Main (string[] args) {
try {
Test1 T1 = new Test1 ();
for (int i=0;i<100;i++) {
New Thread (T1). Start ();
New Thread (T1). Start ();
New Thread (T1). Start ();
New Thread (T1). Start ();
}
} catch (Exception e) {
TODO auto-generated Catch block
E.printstacktrace ();
}
}

public void Run () {
TODO auto-generated Method Stub
Class CLS;
try {
CLS = Class.forName ("Test2");
Test2 action = (Test2) cls.newinstance ();
Action.getrandomstring ();
} catch (Exception e) {
TODO auto-generated Catch block
E.printstacktrace ();
}
}
}

public class Test2 {

public static void Main (string[] args) {

}

/**
* @param args
* @throws interruptedexception
*/
Call the synchronized function of different object, need to add statci adornment, otherwise thread synchronization fails
Public synchronized static void Getrandomstring () throws Interruptedexception {
System.out.println ("$$$$$$$$$$$$$$$$$$");
Thread.Sleep (1000);
Random random = new random ();
int aa = Random.nextint (10);
int bb = Random.nextint (10);
int cc = Random.nextint (10);
System.out.println (string.valueof (aa) +string.valueof (BB) +string.valueof (cc));
System.out.println ("############");
}
}

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Synchronized: Summary of thread synchronization method usage