Java common thread blocking and solutions

/**

 * @author Liangjun

 * @descriptionTODO

* Alphonse Gaston two objects waiting for each other to release a lock , Thread Blocking , cause a deadlock

*/

Public class Friend {

Private final String name;

Public Friend (String name) {

this. name = name;

}

Public String GetName () {

return this. name;

}

Public synchronized void bow (Friend bower) {

System. out. Format ("%s:%s"

+ "have bowed to me!%n",

this. name, Bower.getname ());

Bower.bowback (this);

}

Public synchronized void bowback (friendbower) {

System. out. Format ("%s:%s"

+ "have bowed back to me!%n",

this. name, Bower.getname ());

}

Public static void main (string[] args) {

Final Friend alphonse =

New Friend ("Alphonse");

Final Friend Gaston =

New Friend ("Gaston");

New Thread (new Runnable () {

Public void run () {Alphonse.bow (Gaston);}

}). Start ();

New Thread (new Runnable () {

Public void run () {Gaston.bow (Alphonse);}

}). Start ();

}

}

/**

 * @author Liangjun

 * @descriptionTODO

* 1. multiple threads of the same object are called separately method1 method2 when ,

* 2.ThreadA Get lock lock_1,threadb Get Lock_2,

* 3.ThreadA continue to perform the acquisition lock_2 when, or threadb continue to perform the acquisition Lock_1 when , Lock_2/lock_1 were possessed by each other,

* 4.THREADA/THREADB thread blocking, causing a deadlock phenomenon

*

*/

class Deadlocker {

int field_1;

Private Objectlock_1 =newint[1];

int field_2;

Private Objectlock_2 =newint[1];

Public void method1 (int value) {

synchronized (lock_1) {

Try {

Thread. Sleep (100);

} catch (Interruptedexception e) {

E.printstacktrace ();

}

System. out. println (" current thread:" + thread. ) CurrentThread(). GetName ());

synchronized (lock_2) {

field_1 = 0;

field_2 = 0;

System. out. println ("method1");

}

}

}

Public void method2 (int value) {

synchronized (lock_2) {

System. out. println (" current thread:" + thread. ) CurrentThread(). GetName ());

synchronized (lock_1) {

field_1 = 0;

field_2 = 0;

System. out. println ("method2");

}

}

}

Public static void main (String args[]) {

Final Deadlocker dl =new deadlocker ();

New Thread (new Runnable () {

@Override

Public void run () {

DL.METHOD1 (0);

}

}). Start ();

New Thread (new Runnable () {

@Override

Public void run () {

DL.METHOD2 (1);

}

}). Start ();

}

}

/**

 * solution: Have all threads get a set of locks in the same order

 *        make multiple locks into one group and place them under the same lock

*/

Java common thread blocking and solutions