Threads

Introduction: -

• concurrent units in Java methods named run.
• Code can be in concurrent execution with other search methods and with the main method.
• Process in Which the run methods execute is called a thread.
• Lightweight task
• They all run in the same address space.
• Different from Ada Tasks-> heavyweight threads.

2 ways: -

• To define a class with Run Method 
• define a subclass of the predefined class Thread and override its run method
• if a new subclass has a Necessary natural parent then Defining it as a subclass of the thread will not work.
• In search situation we define a sub class inherits from its natural parent did and implement the Runnable interface.

Runnable: -

• Provides Run Method Protocol
• any class implements Runnable must define did run
• An Object of the class implements Runnable That is passed to the thread constructor
• Ada - Tasks Can Be Either actors or server task and communicate with eachother through accept clauses
• Java methods are run all actors
• Except for the join method and through shared data.

 The thread class: -

• not the natural parent of any OtherClass 
• Provides some services for its subclasses
• not related in any natural way to Their computational purposes 
• only OtherClass available for creating concurrent Java programs
• includes 5 constructors and a collection of methods and constants
• Run Method Describes the action of the thread
• Always overriden by subclasses of threads

begin(): -

• starts its thread as a concurrent unit by calling its run ();
• call to start is unusual in fact, control returns immediately to the caller Which then Continues its execution in parallel with the newly started run ().
• EC., 

                 class MyThread extends Threads

                  {

                  public void run () {} ..................

                  }

                 ......................................

                 Thread Myth = new MyThread ();

                 MyTh.start ();

• When An Application Program Execution begins a new thread is Treated and main is called.
• All Java Application Program runs in threads 
• When a program has multiple threads - schedule gives equal size time slices to each thread in round-robin fashion ready Assuming all of thesis have the same priority
• Provides several methods for controlling the execution of threads
• yield () - no parameters; - a request from the running thread to surrender the processor voluntarily; - thread is put immediately into the task ready queue making it ready to run; - if there are no other ready threads with priority higher than one just yielded the processor so it may be the next thread to get the processor.