multithreading - Using Multiple Threads in Java -

i've been trying understand how multi-threading work ran below code:

/*  * change template, choose tools | templates  * , open template in editor.  */ package mainbowl;  import java.util.logging.level; import java.util.logging.logger;  /**  *  * @author kbluue  */ public class threadstudy {  thread t, t1, t2; runnable r, r1, r2;  public threadstudy() {     init(); }   public void start(){  }  private void init(){     t = new thread(r);     t.setname("thread");     t1 = new thread(r1);     t1.setname("thread 1");     t2 = new thread(r2);     t2.setname("thread 2");      r = new runnable() {          @override         public void run() {            // throw new unsupportedoperationexception("not supported yet.");             if (t != null){                 printstart(t);                 try {                     thread.currentthread().wait();                 } catch (exception e){                     printerror(t);                 }                 printresume(t);                 t1.notify();             }         }     };     r1 = new runnable() {          @override         public void run() {            // throw new unsupportedoperationexception("not supported yet.");             if (t != null){                 printstart(t1);                 try {                     t1.wait();                 } catch (interruptedexception ex) {                     logger.getlogger(threadstudy.class.getname()).log(level.severe, null, ex);                 }                 printresume(t1);                 t2.notify();             }         }     };     r2 = new runnable() {          @override         public void run() {            // throw new unsupportedoperationexception("not supported yet.");             if (t != null){                 printstart(t2);                 t.notify();                 printresume(t2);             }         }     }; }  private void printstart(thread t){     system.out.println("this new thread starting" + t.getname()); }  private void printresume(thread t){     system.out.println("this thread resuming" + t.getname()); } private void printerror(thread t){     system.out.println("there error" + t.getname()); }  public void run(){     t.start();     t1.start();     t2.start(); } 

}

and ran in main activity

new threadstudy().run; 

but output gave nothing. just;

run: build successful (total time: 0 seconds) 

not error message work with.

also i'd know if there more ways add commands/methods thread other new thread(runnable r) method. in anticipation.

it's worth reading here oracle java tutorial - defining , starting thread

an application creates instance of thread must provide code run in thread. there 2 ways this:

• provide runnable object. runnable interface defines single method, run, meant contain code executed in thread. runnable object passed thread constructor.

• subclass thread. thread class implements runnable, though run method nothing. application can subclass thread, providing own implementation of run.

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you can without using runnable interface overriding default run() method of thread class

sample code:

t = new thread(){     @override     public void run() {        // add logic here        // or call method here     } };