Java Multi-threading programming

Java Multi-threading programming

• 1.
  Multithreading Programming  Multithreadingis conceptual programming where a program (processes) are divided into two or more subprograms (processes).  A thread is similar to program that has a single flow of control  It has beginning , body , an end and executes command Sequentially  Every program will have at least one thread. 1 RAJESHREE KHANDE
• 2.
  What are Threads? A piece of code that run in concurrent with other threads.  Each thread is a statically ordered sequence of instructions.  Threads are being extensively used express concurrency on both single and multiprocessors machines. 2 RAJESHREE KHANDE
• 3.
  A single threadedprogram class ABC { …. public void main(..) { … .. } } begin body end 3 RAJESHREE KHANDE
• 4.
  A Multithreaded Program MainThread Thread A Thread B Thread C start start start Threads may switch or exchange data/results Main Method Module SwitchingSwitching 4 RAJESHREE KHANDE
• 5.
  Printing Thread Editing Thread ModernApplications need Threads (ex1): Editing and Printing documents in background. 5 RAJESHREE KHANDE
• 6.
  Thread Class  MultithreadingSystem built upon Thread class it’s method, it’s interface Runnable.  To create a new Thread , either extends Thread or implement the Runnable interface  Thread class defines several Methods. Some of the method are 1) getName() : Obtain a thread Name. 6 RAJESHREE KHANDE
• 7.
  Thread Class 2) getPriority(): Obtain a Thread Priority 3) isAlive() : Determine if the thread is still running 4) join() : Wait for thread to terminate. 5) run() : Entry point for the thread. 6) sleep() : Suspend a thread for a period of time. 7) start() : Start a thread by calling it’s run() method 7 RAJESHREE KHANDE
• 8.
  Creating Thread  Javathreads may be created by: 1. Extending Thread class 2. Implementing the Runnable interface  Java threads are managed by the JVM. 8 RAJESHREE KHANDE
• 9.
  1. Extending Threadclass  Declare a class as extending the Thread class  Create instance of that class  This class must override the run() method which is entry point for the new thread.  It must also call start() to begin the execution of new thread. 9 RAJESHREE KHANDE
• 10.
  Extending Thread class Syntax class MyThread extends Thread { public void run() { // thread body of execution } } 10 RAJESHREE KHANDE
• 11.
   Create athread: MyThread thr1 = new MyThread();  Start Execution of threads: thr1.start();  Create and Execute: new MyThread().start(); 1.Extending Thread class 11 RAJESHREE KHANDE
• 12.
  The Main Thread When Java Program start up one thread begins immediately called Main Thread.  It can be control through a object Thread  For this obtain a reference to it by calling the method currentThread() which is public static member of Thread  It’s General Form static Thread CurrentThread() 12 RAJESHREE KHANDE
• 13.
  Life Cycle ofThread 13 new runnable non-runnable dead wait() sleep() suspend() blocked notify() slept resume() unblocked start() stop() RAJESHREE KHANDE
• 14.
  2: Threads byimplementing Runnable interface class MyThread implements Runnable { ..... public void run() { // thread body of execution } }  Creating Object: MyThread myObject = new MyThread();  Creating Thread Object: Thread thr1 = new Thread( myObject );  Start Execution: thr1.start(); 14 RAJESHREE KHANDE
• 15.
  An example 15 class MyThreadimplements Runnable { public void run() { System.out.println(" this thread is running ... "); } } // end class MyThread class ThreadEx2 { public static void main(String [] args ) { Thread t = new Thread(new MyThread()); // due to implementing the Runnable interface // I can call start(), and this will call run(). t.start(); } // end main() } // end class ThreadEx2 RAJESHREE KHANDE