This section you will see the life cycle of thread in java.
Life Cycle of A Thread
When you are programming with threads, understanding the life cycle of thread is very valuable. While a thread is alive, it is in one of several states. By invoking start() method, it doesn?t mean that the thread has access to CPU and start executing straight away. Several factors determine how it will proceed.
Different states of a thread are :
New state ? After the creations of Thread instance the thread is in this state but before the start() method invocation. At this point, the thread is considered not alive.
Runnable (Ready-to-run) state ? A thread start its life from Runnable state. A thread first enters runnable state after the invoking of start() method but a thread can return to this state after either running, waiting, sleeping or coming back from blocked state also. On this state a thread is waiting for a turn on the processor.
Running state ? A thread is in running state that means the thread is currently executing. There are several ways to enter in Runnable state but there is only one way to enter in Running state: the scheduler select a thread from runnable pool.
Dead state ? A thread can be considered dead when its run() method completes. If any thread comes on this state that means it cannot ever run again.
Blocked - A thread can enter in this state because
of waiting the resources that are hold by another thread.
Different states implementing Multiple-Threads are:
As we have seen different states that may be occur
with the single thread. A running thread can
enter to any non-runnable state, depending on the circumstances. A thread
cannot enters directly to the running state from non-runnable state, firstly
it goes to runnable state. Now lets understand
the some non-runnable states which
may be occur handling the multithreads.
Sleeping ? On this state, the thread is
still alive but it is not runnable, it might be return to runnable state later,
if a particular event occurs. On this state a thread sleeps for a specified
amount of time. You can use the method sleep( ) to stop the running
state of a thread.
Waiting for Notification ? A thread waits
for notification from another thread. The thread sends back to runnable
state after sending notification from another thread.
final void wait(long timeout) throws
final void wait(long timeout, int nanos) throws
final void wait() throws InterruptedException
Blocked on I/O ? The thread waits for
completion of blocking operation. A thread can enter on this state because
of waiting I/O resource. In that case the thread sends back to runnable
state after availability of resources.
Blocked for joint completion ? The thread
can come on this state because of waiting the completion of another thread.
Blocked for lock acquisition ? The thread
can come on this state because of waiting to acquire the lock of an object.
Methods that can be applied apply on a
Some Important Methods defined in
java.lang.Thread are shown in the table:
Returns an object
reference to the thread in which it is invoked.
Retrieve the name of the
thread object or instance.
Start the thread by
calling its runmethod.
This method is the entry
point to execute thread, like the main method for applications.
Suspends a thread for a
specified amount of time (in milliseconds).
This method is used to
determine the thread is running or not.
This method returns the number of active threads in a particular thread group and all its subgroups.
The method interrupt the threads on which it is invoked.
By invoking this method the current thread pause its execution temporarily and allow other threads to execute.
This method and join(long
millisec) Throws InterruptedException. These two methods
are invoked on a thread. These are not returned until either the thread has completed or it is timed out respectively.
April 4, 2012
I found this quite useful. A summary of just what I was looking for.
May 10, 2012
it's really very helpfull.
May 25, 2012
what is life cycle of thread?
June 20, 2012
The explanation of life cycle of thread is easy to understand..
June 29, 2012
life cycle of thread
whats its performance
October 12, 2012
November 21, 2012
How does this life cycle manifest itself in programming code? If anyone can hel[ great.
November 29, 2012
Please correct the thread life cycle diagram. A thread can enter into RUNNING state only from RUNNABLE state but not from BLOCKED state. The diagram above says that WAITING and RUNNING states communicate with each other. But the fact is, A Thread can enter WAITING state from RUNNING state but not the vice-versa.