How to check if a thread is already started or not in Java? [duplicate]

Answer 1

You can use Thread.getState() and use the corresponding states.

Note that by the time you read this state it may have changed, but you may be able to determine something of interest. Check out this state diagram for the available transitions.

Answer 2

I use this code Thread.isAlive()

Answer 3

You can use GetState()

Returns the state of this thread. This method is designed for use in monitoring of the system state, not for synchronization control.

or boolean isAlive()

Tests if this thread is alive. A thread is alive if it has been started and has not yet died.

Answer 4

Thread.isAlive() can determine if a thread is running.

Tests if this thread is alive. A thread is alive if it has been started and has not yet died.

Thread#getState(); can return the exact state of a thread.

Returns the state of this thread. This method is designed for use in monitoring of the system state, not for synchronization control.

Answer 5

Use either Thread#isAlive()

if (Thread.currentThread().isAlive())

JavaDoc says:

Tests if this thread is alive. A thread is alive if it has been started and has not yet died.

Or, use Thread#getState() as

Thread.State currState = Thread.currentThread().getState();
if (currState != Thread.State.NEW && currState != Thread.State.TERMINATED)

JavaDoc says:

Returns the state of this thread. This method is designed for use in monitoring of the system state, not for synchronization control.

Answer 6

You can check it with isAlive..

isAlive tests if this thread is alive. A thread is alive if it has been started and has not yet died.