Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Lecture 20


Published on

Notes on core java

Published in: Technology, Education
  • Be the first to comment

  • Be the first to like this

Lecture 20

  1. 1. Core Java Debasish Pratihari Thread  A thread is the basic unit to which the operating system allocates processor time.  Threads are useful to execute more or less independent code segments concurrently of a program.  Is knows as light-weight process.  Threads are always owned and managed by operating system.  Every program has at least one thread. User Thread  A user thread has a life-time of its own.  It is not depended on the thread that creates it.  It can continue execution after the thread that created has ended. Daemon Thread  Is a background thread that sub-ordinate to the thread that creates it  When the thread that created the daemon thread ends, the daemon thread dies with it.  A thread can be set to daemon before it starts  Threads created from daemon thread are daemon by default. Lecture/core/thread1/20 Page #1 feel the Technology…
  2. 2. Core Java Debasish Pratihari Process  It has its own address space.  A process can’t access another process’s memory .  Each process provides the resources needed to execute a program.  Threads belongs to same process shares same address space.  A process has at least one thread of execution. Thread Objects:  Each thread is associated with an instance of the class Thread  There are two ways for using thread object  Directly controlling thread  Using executor Creating Thread  Provide a Runnable Object class Lakshya implements Runnable{ --}  Sub class Thread class Lakshya extends Thread{ --} Lecture/core/thread1/20 Page #2 feel the Technology…
  3. 3. Core Java Debasish Pratihari Thread State:  New Born State: When we create a Thread Object then a Thread is born.  Runnable State: When we call the start( ) method on a thread then thread is in the Runnable state i.e., the threads in Runnable state are all waiting in a queue for the availability of CPU attention or their turns to come.  Running State: When a thread got the time of CPU then it starts execution for a particular interval of time (time slice) this state is called as Running state.  Blocked state: A thread is in the blocked state when it is prevented to entered into Runnable state.  Dead state: This is the end of life of a thread, when a thread completes execution comes to the dead state. Also we can dead state by calling stop( ) method. New Born Start ( ) sleep ( ) Runnable State Stop ( ) Scheduling Dead State Lecture/core/thread1/20 Running State Block State after time-slice or yield( ) Page #3 feel the Technology…
  4. 4. Core Java  Debasish Pratihari A Thread enters into blocked state under the following situation.     By sleeping a thread. If a thread is waiting for I/O operation. If a thread is Interrupted. If a thread is waiting for lock available. Thread Life-Cycle 25% New Born start( ) start ( ) notify( )/ notifyAll ( ) Runnable State wait lock available I/O complete after t time Scheduling mechanism after time slice sleep( ) wait( ) Running State wait for Lock wait for I/O sleep( t ) B L O C K E D S T A T E Dead State Lecture/core/thread1/20 Page #4 feel the Technology…