: Class Thread

java.lang.Object
  |
  +--java.lang.Thread

All Implemented Interfaces:: Runnable

public class Thread
extends Object
implements Runnable

A thread is a thread of execution in a program. The Java Virtual Machine allows an application to have multiple threads of execution running concurrently.

Every thread has a priority. Threads with higher priority are executed in preference to threads with lower priority. Each thread may or may not also be marked as a daemon. When code running in some thread creates a new Thread object, the new thread has its priority initially set equal to the priority of the creating thread, and is a daemon thread if and only if the creating thread is a daemon.

When a Java Virtual Machine starts up, there is usually a single non-daemon thread (which typically calls the method named main of some designated class). The Java Virtual Machine continues to execute threads until either of the following occurs:

The exit method of class Runtime has been called and the security manager has permitted the exit operation to take place.
All threads that are not daemon threads have died, either by returning from the call to the run method or by throwing an exception that propagates beyond the run method.

There are two ways to create a new thread of execution. One is to declare a class to be a subclass of Thread. This subclass should override the run method of class Thread. An instance of the subclass can then be allocated and started. For example, a thread that computes primes larger than a stated value could be written as follows:

     class PrimeThread extends Thread {
         long minPrime;
         PrimeThread(long minPrime) {
             this.minPrime = minPrime;
         }
 
         public void run() {
             // compute primes larger than minPrime
              . . .
         }
     }

The following code would then create a thread and start it running:

     PrimeThread p = new PrimeThread(143);
     p.start();

The other way to create a thread is to declare a class that implements the Runnable interface. That class then implements the run method. An instance of the class can then be allocated, passed as an argument when creating Thread, and started. The same example in this other style looks like the following:

     class PrimeRun implements Runnable {
         long minPrime;
         PrimeRun(long minPrime) {
             this.minPrime = minPrime;
         }
 
         public void run() {
             // compute primes larger than minPrime
              . . .
         }
     }

The following code would then create a thread and start it running:

     PrimeRun p = new PrimeRun(143);
     new Thread(p).start();

Every thread has a name for identification purposes. More than one thread may have the same name. If a name is not specified when a thread is created, a new name is generated for it.

Since:: JDK1.0
See Also:: Runnable, Runtime.exit(int), run(), stop()

Field Summary

static int MAX_PRIORITY
copy-> MAX_PRIORITY

The maximum priority that a thread can have.

static int MIN_PRIORITY
copy-> MIN_PRIORITY

The minimum priority that a thread can have.

static int NORM_PRIORITY
copy-> NORM_PRIORITY

The default priority that is assigned to a thread.

Constructor Summary

Thread
copy-> new Thread()
copy-> <Thread var> = new Thread();

Allocates a new Thread object. This constructor has the same effect as Thread(null, null, gname), where gname is a newly generated name. Automatically generated names are of the form "Thread-"+n, where n is an integer.
Threads created this way must have overridden their run() method to actually do anything. An example illustrating this method being used follows:
import java.lang.*; class plain01 implements Runnable { String name; plain01() { name = null; } plain01(String s) { name = s; } public void run() { if (name == null) System.out.println("A new thread created"); else System.out.println("A new thread with name " + name + " created"); } } class threadtest01 { public static void main(String args[] ) { int failed = 0 ; Thread t1 = new Thread(); if (t1 != null) System.out.println("new Thread() succeed"); else { System.out.println("new Thread() failed"); failed++; } } }

See Also:
Thread(java.lang.ThreadGroup, java.lang.Runnable, java.lang.String)

Thread
copy-> new Thread( )
copy-> <Thread var> = new Thread(<Runnable target>);

Allocates a new Thread object. This constructor has the same effect as Thread(null, target, gname), where gname is a newly generated name. Automatically generated names are of the form "Thread-"+n, where n is an integer.

Parameters:
target - the object whose run method is called.
See Also:
Thread(java.lang.ThreadGroup, java.lang.Runnable, java.lang.String)

Thread
copy-> new Thread(, )
copy-> <Thread var> = new Thread(<Runnable target>, <String name>);

Allocates a new Thread object. This constructor has the same effect as Thread(null, target, name).

Parameters:
target - the object whose run method is called.
name - the name of the new thread.
See Also:
Thread(java.lang.ThreadGroup, java.lang.Runnable, java.lang.String)

Thread
copy-> new Thread( )
copy-> <Thread var> = new Thread(<String name>);

Allocates a new Thread object. This constructor has the same effect as Thread(null, null, name).

Parameters:
name - the name of the new thread.
See Also:
Thread(java.lang.ThreadGroup, java.lang.Runnable, java.lang.String)

Thread
copy-> new Thread(, )
copy-> <Thread var> = new Thread(<ThreadGroup group>, <Runnable target>);

Allocates a new Thread object. This constructor has the same effect as Thread(group, target, gname), where gname is a newly generated name. Automatically generated names are of the form "Thread-"+n, where n is an integer.

Parameters:
group - the thread group.
target - the object whose run method is called.
Throws:
SecurityException - if the current thread cannot create a thread in the specified thread group.
See Also:
Thread(java.lang.ThreadGroup, java.lang.Runnable, java.lang.String)

Thread
copy-> new Thread(, , )
copy-> <Thread var> = new Thread(<ThreadGroup group>, <Runnable target>, <String name>);

Allocates a new Thread object so that it has target as its run object, has the specified name as its name, and belongs to the thread group referred to by group.
If group is null, the group is set to be the same ThreadGroup as the thread that is creating the new thread.
If there is a security manager, its checkAccess method is called with the ThreadGroup as its argument. This may result in a SecurityException.
If the target argument is not null, the run method of the target is called when this thread is started. If the target argument is null, this thread's run method is called when this thread is started.
The priority of the newly created thread is set equal to the priority of the thread creating it, that is, the currently running thread. The method setPriority may be used to change the priority to a new value.
The newly created thread is initially marked as being a daemon thread if and only if the thread creating it is currently marked as a daemon thread. The method setDaemon may be used to change whether or not a thread is a daemon.

Parameters:
group - the thread group.
target - the object whose run method is called.
name - the name of the new thread.
Throws:
SecurityException - if the current thread cannot create a thread in the specified thread group.
See Also:
Runnable.run(), run(), setDaemon(boolean), setPriority(int), ThreadGroup.checkAccess(), SecurityManager.checkAccess(java.lang.Thread)

Thread
copy-> new Thread(, )
copy-> <Thread var> = new Thread(<ThreadGroup group>, <String name>);

Allocates a new Thread object. This constructor has the same effect as Thread(group, null, name)

Parameters:
group - the thread group.
name - the name of the new thread.
Throws:
SecurityException - if the current thread cannot create a thread in the specified thread group.
See Also:
Thread(java.lang.ThreadGroup, java.lang.Runnable, java.lang.String)

Method Summary

static int activeCount()
copy-> Thread.activeCount()
copy-> <int var>=Thread.activeCount();

Returns the current number of active threads in this thread's thread group.

Returns:
the current number of threads in this thread's thread group.

void checkAccess()
copy-> .checkAccess()
copy-> <Thread>.checkAccess();

Determines if the currently running thread has permission to modify this thread.
If there is a security manager, its checkAccess method is called with this thread as its argument. This may result in throwing a SecurityException.
Note: This method was mistakenly non-final in JDK 1.1. It has been made final in the Java 2 Platform.

Throws:
SecurityException - if the current thread is not allowed to access this thread.
See Also:
SecurityManager.checkAccess(java.lang.Thread)

int countStackFrames()
copy-> .countStackFrames()
copy-> <int var>=<Thread>.countStackFrames();

Deprecated. The definition of this call depends on suspend(), which is deprecated. Further, the results of this call were never well-defined.

Counts the number of stack frames in this thread. The thread must be suspended.

Returns:
the number of stack frames in this thread.
Throws:
IllegalThreadStateException - if this thread is not suspended.

static Thread currentThread()
copy-> Thread.currentThread()
copy-> <Thread var>=Thread.currentThread();

Returns a reference to the currently executing thread object.

Returns:
the currently executing thread.

void destroy()
copy-> .destroy()
copy-> <Thread>.destroy();

Destroys this thread, without any cleanup. Any monitors it has locked remain locked. (This method is not implemented.)

static void dumpStack()
copy-> Thread.dumpStack()
copy-> Thread.dumpStack();

Prints a stack trace of the current thread. This method is used only for debugging.

See Also:
Throwable.printStackTrace()

static int enumerate(Thread[] tarray)
copy-> Thread.enumerate( )
copy-> <int var>=Thread.enumerate(<Thread[] tarray>);

Copies into the specified array every active thread in this thread's thread group and its subgroups. This method simply calls the enumerate method of this thread's thread group with the array argument.
First, if there is a security manager, that enumerate method calls the security manager's checkAccess method with the thread group as its argument. This may result in throwing a SecurityException.

Parameters:
tarray - an array of Thread objects to copy to
Returns:
the number of threads put into the array
Throws:
SecurityException - if a security manager exists and its checkAccess method doesn't allow the operation.
See Also:
ThreadGroup.enumerate(java.lang.Thread[]), SecurityManager.checkAccess(java.lang.ThreadGroup)

ClassLoader getContextClassLoader()
copy-> .getContextClassLoader()
copy-> <ClassLoader var>=<Thread>.getContextClassLoader();

Returns the context ClassLoader for this Thread. The context ClassLoader is provided by the creator of the thread for use by code running in this thread when loading classes and resources. If not set, the default is the ClassLoader context of the parent Thread. The context ClassLoader of the primordial thread is typically set to the class loader used to load the application.
First, if there is a security manager, and the caller's class loader is not null and the caller's class loader is not the same as or an ancestor of the context class loader for the thread whose context class loader is being requested, then the security manager's checkPermission method is called with a RuntimePermission("getClassLoader") permission to see if it's ok to get the context ClassLoader..

Returns:
the context ClassLoader for this Thread
Throws:
SecurityException - if a security manager exists and its checkPermission method doesn't allow getting the context ClassLoader.
Since:
1.2

See Also:
setContextClassLoader(java.lang.ClassLoader), SecurityManager.checkPermission(java.security.Permission), RuntimePermission

String getName()
copy-> .getName()
copy-> <String var>=<Thread>.getName();

Returns this thread's name.

Returns:
this thread's name.
See Also:
setName(java.lang.String), setName(java.lang.String)

int getPriority()
copy-> .getPriority()
copy-> <int var>=<Thread>.getPriority();

Returns this thread's priority.

Returns:
this thread's name.
See Also:
setPriority(int), setPriority(int)

ThreadGroup getThreadGroup()
copy-> .getThreadGroup()
copy-> <ThreadGroup var>=<Thread>.getThreadGroup();

Returns the thread group to which this thread belongs. This method returns null if this thread has died (been stopped).

Returns:
this thread's thread group.

void interrupt()
copy-> .interrupt()
copy-> <Thread>.interrupt();

Interrupts this thread.
First the checkAccess method of this thread is called with no arguments. This may result in throwing a SecurityException.

Throws:
SecurityException - if the current thread cannot modify this thread.

static boolean interrupted()
copy-> Thread.interrupted()
copy-> <boolean var>=Thread.interrupted();

Tests whether the current thread has been interrupted. The interrupted status of the thread is cleared by this method. In other words, if this method were to be called twice in succession, the second call would return false (unless the current thread were interrupted again, after the first call had cleared its interrupted status and before the second call had examined it).

Returns:
true if the current thread has been interrupted; false otherwise.
See Also:
isInterrupted()

boolean isAlive()
copy-> .isAlive()
copy-> <boolean var>=<Thread>.isAlive();

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

Returns:
true if this thread is alive; false otherwise.

boolean isDaemon()
copy-> .isDaemon()
copy-> <boolean var>=<Thread>.isDaemon();

Tests if this thread is a daemon thread.

Returns:
true if this thread is a daemon thread; false otherwise.
See Also:
setDaemon(boolean)

boolean isInterrupted()
copy-> .isInterrupted()
copy-> <boolean var>=<Thread>.isInterrupted();

Tests whether this thread has been interrupted. The interrupted status of the thread is unaffected by this method.

Returns:
true if this thread has been interrupted; false otherwise.
See Also:
interrupted()

void join()
copy-> .join()
copy-> <Thread>.join();

Waits for this thread to die.

Throws:
InterruptedException - if another thread has interrupted the current thread. The interrupted status of the current thread is cleared when this exception is thrown.

void join(long millis)
copy-> .join( )
copy-> <Thread>.join(<long millis>);

Waits at most millis milliseconds for this thread to die. A timeout of 0 means to wait forever.

Parameters:
millis - the time to wait in milliseconds.
Throws:
InterruptedException - if another thread has interrupted the current thread. The interrupted status of the current thread is cleared when this exception is thrown.

void join(long millis, int nanos)
copy-> .join(, )
copy-> <Thread>.join(<long millis>, <int nanos>);

Waits at most millis milliseconds plus nanos nanoseconds for this thread to die.

Parameters:
millis - the time to wait in milliseconds.
nanos - 0-999999 additional nanoseconds to wait.
Throws:
IllegalArgumentException - if the value of millis is negative the value of nanos is not in the range 0-999999.
InterruptedException - if another thread has interrupted the current thread. The interrupted status of the current thread is cleared when this exception is thrown.

void resume()
copy-> .resume()
copy-> <Thread>.resume();

Deprecated. This method exists solely for use with suspend(), which has been deprecated because it is deadlock-prone. For more information, see Why are Thread.stop, Thread.suspend and Thread.resume Deprecated?.

Resumes a suspended thread.
First, the checkAccess method of this thread is called with no arguments. This may result in throwing a SecurityException (in the current thread).
If the thread is alive but suspended, it is resumed and is permitted to make progress in its execution.

Throws:
SecurityException - if the current thread cannot modify this thread.
See Also:
checkAccess(), suspend()

void run()
copy-> .run()
copy-> <Thread>.run();

If this thread was constructed using a separate Runnable run object, then that Runnable object's run method is called; otherwise, this method does nothing and returns.
Subclasses of Thread should override this method.

Specified by:
run in interface Runnable

See Also:
start(), stop(), Thread(java.lang.ThreadGroup, java.lang.Runnable, java.lang.String), Runnable.run()

void setContextClassLoader(ClassLoader cl)
copy-> .setContextClassLoader( )
copy-> <Thread>.setContextClassLoader(<ClassLoader cl>);

Sets the context ClassLoader for this Thread. The context ClassLoader can be set when a thread is created, and allows the creator of the thread to provide the appropriate class loader to code running in the thread when loading classes and resources.
First, if there is a security manager, its checkPermission method is called with a RuntimePermission("setContextClassLoader") permission to see if it's ok to set the context ClassLoader..

Parameters:
cl - the context ClassLoader for this Thread
Throws:
SecurityException - if the current thread cannot set the context ClassLoader.
Since:
1.2

See Also:
getContextClassLoader(), SecurityManager.checkPermission(java.security.Permission), RuntimePermission

void setDaemon(boolean on)
copy-> .setDaemon( )
copy-> <Thread>.setDaemon(<boolean on>);

Marks this thread as either a daemon thread or a user thread. The Java Virtual Machine exits when the only threads running are all daemon threads.
This method must be called before the thread is started.
This method first calls the checkAccess method of this thread with no arguments. This may result in throwing a SecurityException (in the current thread).

Parameters:
on - if true, marks this thread as a daemon thread.
Throws:
IllegalThreadStateException - if this thread is active.
SecurityException - if the current thread cannot modify this thread.
See Also:
isDaemon(), checkAccess()

void setName(String name)
copy-> .setName( )
copy-> <Thread>.setName(<String name>);

Changes the name of this thread to be equal to the argument name.
First the checkAccess method of this thread is called with no arguments. This may result in throwing a SecurityException.

Parameters:
name - the new name for this thread.
Throws:
SecurityException - if the current thread cannot modify this thread.
See Also:
getName(), checkAccess(), getName()

void setPriority(int newPriority)
copy-> .setPriority( )
copy-> <Thread>.setPriority(<int newPriority>);

Changes the priority of this thread.
First the checkAccess method of this thread is called with no arguments. This may result in throwing a SecurityException.
Otherwise, the priority of this thread is set to the smaller of the specified newPriority and the maximum permitted priority of the thread's thread group.

Parameters:
newPriority - priority to set this thread to
Throws:
IllegalArgumentException - If the priority is not in the range MIN_PRIORITY to MAX_PRIORITY.
SecurityException - if the current thread cannot modify this thread.
See Also:
getPriority(), checkAccess(), getPriority(), getThreadGroup(), MAX_PRIORITY, MIN_PRIORITY, ThreadGroup.getMaxPriority()

static void sleep(long millis)
copy-> Thread.sleep( )
copy-> Thread.sleep(<long millis>);

Causes the currently executing thread to sleep (temporarily cease execution) for the specified number of milliseconds. The thread does not lose ownership of any monitors.

Parameters:
millis - the length of time to sleep in milliseconds.
Throws:
InterruptedException - if another thread has interrupted the current thread. The interrupted status of the current thread is cleared when this exception is thrown.
See Also:
Object.notify()

static void sleep(long millis, int nanos)
copy-> Thread.sleep(, )
copy-> Thread.sleep(<long millis>, <int nanos>);

Causes the currently executing thread to sleep (cease execution) for the specified number of milliseconds plus the specified number of nanoseconds. The thread does not lose ownership of any monitors.

Parameters:
millis - the length of time to sleep in milliseconds.
nanos - 0-999999 additional nanoseconds to sleep.
Throws:
IllegalArgumentException - if the value of millis is negative or the value of nanos is not in the range 0-999999.
InterruptedException - if another thread has interrupted the current thread. The interrupted status of the current thread is cleared when this exception is thrown.
See Also:
Object.notify()

void start()
copy-> .start()
copy-> <Thread>.start();

Causes this thread to begin execution; the Java Virtual Machine calls the run method of this thread.
The result is that two threads are running concurrently: the current thread (which returns from the call to the start method) and the other thread (which executes its run method).

Throws:
IllegalThreadStateException - if the thread was already started.
See Also:
run(), stop()

void stop()
copy-> .stop()
copy-> <Thread>.stop();

Deprecated. This method is inherently unsafe. Stopping a thread with Thread.stop causes it to unlock all of the monitors that it has locked (as a natural consequence of the unchecked ThreadDeath exception propagating up the stack). If any of the objects previously protected by these monitors were in an inconsistent state, the damaged objects become visible to other threads, potentially resulting in arbitrary behavior. Many uses of stop should be replaced by code that simply modifies some variable to indicate that the target thread should stop running. The target thread should check this variable regularly, and return from its run method in an orderly fashion if the variable indicates that it is to stop running. If the target thread waits for long periods (on a condition variable, for example), the interrupt method should be used to interrupt the wait. For more information, see Why are Thread.stop, Thread.suspend and Thread.resume Deprecated?.

Forces the thread to stop executing.
If there is a security manager installed, its checkAccess method is called with this as its argument. This may result in a SecurityException being raised (in the current thread).
If this thread is different from the current thread (that is, the current thread is trying to stop a thread other than itself), the security manager's checkPermission method (with a RuntimePermission("stopThread") argument) is called in addition. Again, this may result in throwing a SecurityException (in the current thread).
The thread represented by this thread is forced to stop whatever it is doing abnormally and to throw a newly created ThreadDeath object as an exception.
It is permitted to stop a thread that has not yet been started. If the thread is eventually started, it immediately terminates.
An application should not normally try to catch ThreadDeath unless it must do some extraordinary cleanup operation (note that the throwing of ThreadDeath causes finally clauses of try statements to be executed before the thread officially dies). If a catch clause catches a ThreadDeath object, it is important to rethrow the object so that the thread actually dies.
The top-level error handler that reacts to otherwise uncaught exceptions does not print out a message or otherwise notify the application if the uncaught exception is an instance of ThreadDeath.

Throws:
SecurityException - if the current thread cannot modify this thread.
See Also:
interrupt(), checkAccess(), run(), start(), ThreadDeath, ThreadGroup.uncaughtException(java.lang.Thread, java.lang.Throwable), SecurityManager.checkAccess(Thread), SecurityManager.checkPermission(java.security.Permission)

void stop(Throwable obj)
copy-> .stop( )
copy-> <Thread>.stop(<Throwable obj>);

Deprecated. This method is inherently unsafe. See stop() (with no arguments) for details. An additional danger of this method is that it may be used to generate exceptions that the target thread is unprepared to handle (including checked exceptions that the thread could not possibly throw, were it not for this method). For more information, see Why are Thread.stop, Thread.suspend and Thread.resume Deprecated?.

Forces the thread to stop executing.
If there is a security manager installed, the checkAccess method of this thread is called, which may result in a SecurityException being raised (in the current thread).
If this thread is different from the current thread (that is, the current thread is trying to stop a thread other than itself) or obj is not an instance of ThreadDeath, the security manager's checkPermission method (with the RuntimePermission("stopThread") argument) is called in addition. Again, this may result in throwing a SecurityException (in the current thread).
If the argument obj is null, a NullPointerException is thrown (in the current thread).
The thread represented by this thread is forced to complete whatever it is doing abnormally and to throw the Throwable object obj as an exception. This is an unusual action to take; normally, the stop method that takes no arguments should be used.
It is permitted to stop a thread that has not yet been started. If the thread is eventually started, it immediately terminates.

Parameters:
obj - the Throwable object to be thrown.
Throws:
SecurityException - if the current thread cannot modify this thread.
See Also:
interrupt(), checkAccess(), run(), start(), stop(), SecurityManager.checkAccess(Thread), SecurityManager.checkPermission(java.security.Permission)

void suspend()
copy-> .suspend()
copy-> <Thread>.suspend();

Deprecated. This method has been deprecated, as it is inherently deadlock-prone. If the target thread holds a lock on the monitor protecting a critical system resource when it is suspended, no thread can access this resource until the target thread is resumed. If the thread that would resume the target thread attempts to lock this monitor prior to calling resume, deadlock results. Such deadlocks typically manifest themselves as "frozen" processes. For more information, see Why are Thread.stop, Thread.suspend and Thread.resume Deprecated?.

Suspends this thread.
First, the checkAccess method of this thread is called with no arguments. This may result in throwing a SecurityException (in the current thread).
If the thread is alive, it is suspended and makes no further progress unless and until it is resumed.

Throws:
SecurityException - if the current thread cannot modify this thread.
See Also:
checkAccess()

String toString()
copy-> .toString()
copy-> <String var>=<Thread>.toString();

Returns a string representation of this thread, including the thread's name, priority, and thread group.

Overrides:
toString in class Object

Returns:
a string representation of this thread.

static void yield()
copy-> Thread.yield()
copy-> Thread.yield();

Causes the currently executing thread object to temporarily pause and allow other threads to execute.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

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Field Summary
`static int`	MAX_PRIORITY copy-> `MAX_PRIORITY` The maximum priority that a thread can have.
`static int`	MIN_PRIORITY copy-> `MIN_PRIORITY` The minimum priority that a thread can have.
`static int`	NORM_PRIORITY copy-> `NORM_PRIORITY` The default priority that is assigned to a thread.

Constructor Summary
Thread copy-> `new Thread()` copy-> `<Thread var> = new Thread();` Allocates a new `Thread` object. This constructor has the same effect as `Thread(null, null,` gname`)`, where *gname* is a newly generated name. Automatically generated names are of the form `"Thread-"+`n, where n is an integer. Threads created this way must have overridden their `run()` method to actually do anything. An example illustrating this method being used follows: import java.lang.; class plain01 implements Runnable { String name; plain01() { name = null; } plain01(String s) { name = s; } public void run() { if (name == null) System.out.println("A new thread created"); else System.out.println("A new thread with name " + name + " created"); } } class threadtest01 { public static void main(String args[] ) { int failed = 0 ; Thread t1 = new Thread();* if (t1 != null) System.out.println("new Thread() succeed"); else { System.out.println("new Thread() failed"); failed++; } } } See Also: `Thread(java.lang.ThreadGroup, java.lang.Runnable, java.lang.String)`
Thread copy-> `new Thread( )` copy-> `<Thread var> = new Thread(<Runnable target>);` Allocates a new `Thread` object. This constructor has the same effect as `Thread(null, target,` gname`)`, where gname is a newly generated name. Automatically generated names are of the form `"Thread-"+`n, where n is an integer. Parameters: `target` - the object whose `run` method is called. See Also: `Thread(java.lang.ThreadGroup, java.lang.Runnable, java.lang.String)`
Thread copy-> `new Thread(, )` copy-> `<Thread var> = new Thread(<Runnable target>, <String name>);` Allocates a new `Thread` object. This constructor has the same effect as `Thread(null, target, name)`. Parameters: `target` - the object whose `run` method is called. `name` - the name of the new thread. See Also: `Thread(java.lang.ThreadGroup, java.lang.Runnable, java.lang.String)`
Thread copy-> `new Thread( )` copy-> `<Thread var> = new Thread(<String name>);` Allocates a new `Thread` object. This constructor has the same effect as `Thread(null, null, name)`. Parameters: `name` - the name of the new thread. See Also: `Thread(java.lang.ThreadGroup, java.lang.Runnable, java.lang.String)`
Thread copy-> `new Thread(, )` copy-> `<Thread var> = new Thread(<ThreadGroup group>, <Runnable target>);` Allocates a new `Thread` object. This constructor has the same effect as `Thread(group, target,` gname`)`, where gname is a newly generated name. Automatically generated names are of the form `"Thread-"+`n, where n is an integer. Parameters: `group` - the thread group. `target` - the object whose `run` method is called. Throws: `SecurityException` - if the current thread cannot create a thread in the specified thread group. See Also: `Thread(java.lang.ThreadGroup, java.lang.Runnable, java.lang.String)`
Thread copy-> `new Thread(, , )` copy-> `<Thread var> = new Thread(<ThreadGroup group>, <Runnable target>, <String name>);` Allocates a new `Thread` object so that it has `target` as its run object, has the specified `name` as its name, and belongs to the thread group referred to by `group`. If `group` is `null`, the group is set to be the same ThreadGroup as the thread that is creating the new thread. If there is a security manager, its `checkAccess` method is called with the ThreadGroup as its argument. This may result in a SecurityException. If the `target` argument is not `null`, the `run` method of the `target` is called when this thread is started. If the target argument is `null`, this thread's `run` method is called when this thread is started. The priority of the newly created thread is set equal to the priority of the thread creating it, that is, the currently running thread. The method `setPriority` may be used to change the priority to a new value. The newly created thread is initially marked as being a daemon thread if and only if the thread creating it is currently marked as a daemon thread. The method `setDaemon` may be used to change whether or not a thread is a daemon. Parameters: `group` - the thread group. `target` - the object whose `run` method is called. `name` - the name of the new thread. Throws: `SecurityException` - if the current thread cannot create a thread in the specified thread group. See Also: `Runnable.run()`, `run()`, `setDaemon(boolean)`, `setPriority(int)`, `ThreadGroup.checkAccess()`, `SecurityManager.checkAccess(java.lang.Thread)`
Thread copy-> `new Thread(, )` copy-> `<Thread var> = new Thread(<ThreadGroup group>, <String name>);` Allocates a new `Thread` object. This constructor has the same effect as `Thread(group, null, name)` Parameters: `group` - the thread group. `name` - the name of the new thread. Throws: `SecurityException` - if the current thread cannot create a thread in the specified thread group. See Also: `Thread(java.lang.ThreadGroup, java.lang.Runnable, java.lang.String)`

Method Summary
`static int`	activeCount() copy-> `Thread.activeCount()` copy-> `<int var>=Thread.activeCount();` Returns the current number of active threads in this thread's thread group. Returns: the current number of threads in this thread's thread group.
`void`	checkAccess() copy-> `.checkAccess()` copy-> `<Thread>.checkAccess();` Determines if the currently running thread has permission to modify this thread. If there is a security manager, its `checkAccess` method is called with this thread as its argument. This may result in throwing a `SecurityException`. Note: This method was mistakenly non-final in JDK 1.1. It has been made final in the Java 2 Platform. Throws: `SecurityException` - if the current thread is not allowed to access this thread. See Also: `SecurityManager.checkAccess(java.lang.Thread)`
`int`	countStackFrames() copy-> `.countStackFrames()` copy-> `<int var>=<Thread>.countStackFrames();` Deprecated. The definition of this call depends on `suspend()`, which is deprecated. Further, the results of this call were never well-defined. Counts the number of stack frames in this thread. The thread must be suspended. Returns: the number of stack frames in this thread. Throws: `IllegalThreadStateException` - if this thread is not suspended.
`static Thread`	currentThread() copy-> `Thread.currentThread()` copy-> `<Thread var>=Thread.currentThread();` Returns a reference to the currently executing thread object. Returns: the currently executing thread.
`void`	destroy() copy-> `.destroy()` copy-> `<Thread>.destroy();` Destroys this thread, without any cleanup. Any monitors it has locked remain locked. (This method is not implemented.)
`static void`	dumpStack() copy-> `Thread.dumpStack()` copy-> `Thread.dumpStack();` Prints a stack trace of the current thread. This method is used only for debugging. See Also: `Throwable.printStackTrace()`
`static int`	enumerate(Thread[] tarray) copy-> `Thread.enumerate( )` copy-> `<int var>=Thread.enumerate(<Thread[] tarray>);` Copies into the specified array every active thread in this thread's thread group and its subgroups. This method simply calls the `enumerate` method of this thread's thread group with the array argument. First, if there is a security manager, that `enumerate` method calls the security manager's `checkAccess` method with the thread group as its argument. This may result in throwing a `SecurityException`. Parameters: `tarray` - an array of Thread objects to copy to Returns: the number of threads put into the array Throws: `SecurityException` - if a security manager exists and its `checkAccess` method doesn't allow the operation. See Also: `ThreadGroup.enumerate(java.lang.Thread[])`, `SecurityManager.checkAccess(java.lang.ThreadGroup)`
`ClassLoader`	getContextClassLoader() copy-> `.getContextClassLoader()` copy-> `<ClassLoader var>=<Thread>.getContextClassLoader();` Returns the context ClassLoader for this Thread. The context ClassLoader is provided by the creator of the thread for use by code running in this thread when loading classes and resources. If not set, the default is the ClassLoader context of the parent Thread. The context ClassLoader of the primordial thread is typically set to the class loader used to load the application. First, if there is a security manager, and the caller's class loader is not null and the caller's class loader is not the same as or an ancestor of the context class loader for the thread whose context class loader is being requested, then the security manager's `checkPermission` method is called with a `RuntimePermission("getClassLoader")` permission to see if it's ok to get the context ClassLoader.. Returns: the context ClassLoader for this Thread Throws: `SecurityException` - if a security manager exists and its `checkPermission` method doesn't allow getting the context ClassLoader. Since: 1.2 See Also: `setContextClassLoader(java.lang.ClassLoader)`, `SecurityManager.checkPermission(java.security.Permission)`, `RuntimePermission`
`String`	getName() copy-> `.getName()` copy-> `<String var>=<Thread>.getName();` Returns this thread's name. Returns: this thread's name. See Also: `setName(java.lang.String)`, `setName(java.lang.String)`
`int`	getPriority() copy-> `.getPriority()` copy-> `<int var>=<Thread>.getPriority();` Returns this thread's priority. Returns: this thread's name. See Also: `setPriority(int)`, `setPriority(int)`
`ThreadGroup`	getThreadGroup() copy-> `.getThreadGroup()` copy-> `<ThreadGroup var>=<Thread>.getThreadGroup();` Returns the thread group to which this thread belongs. This method returns null if this thread has died (been stopped). Returns: this thread's thread group.
`void`	interrupt() copy-> `.interrupt()` copy-> `<Thread>.interrupt();` Interrupts this thread. First the `checkAccess` method of this thread is called with no arguments. This may result in throwing a `SecurityException`. Throws: `SecurityException` - if the current thread cannot modify this thread.
`static boolean`	interrupted() copy-> `Thread.interrupted()` copy-> `<boolean var>=Thread.interrupted();` Tests whether the current thread has been interrupted. The interrupted status of the thread is cleared by this method. In other words, if this method were to be called twice in succession, the second call would return false (unless the current thread were interrupted again, after the first call had cleared its interrupted status and before the second call had examined it). Returns: `true` if the current thread has been interrupted; `false` otherwise. See Also: `isInterrupted()`
`boolean`	isAlive() copy-> `.isAlive()` copy-> `<boolean var>=<Thread>.isAlive();` Tests if this thread is alive. A thread is alive if it has been started and has not yet died. Returns: `true` if this thread is alive; `false` otherwise.
`boolean`	isDaemon() copy-> `.isDaemon()` copy-> `<boolean var>=<Thread>.isDaemon();` Tests if this thread is a daemon thread. Returns: `true` if this thread is a daemon thread; `false` otherwise. See Also: `setDaemon(boolean)`
`boolean`	isInterrupted() copy-> `.isInterrupted()` copy-> `<boolean var>=<Thread>.isInterrupted();` Tests whether this thread has been interrupted. The interrupted status of the thread is unaffected by this method. Returns: `true` if this thread has been interrupted; `false` otherwise. See Also: `interrupted()`
`void`	join() copy-> `.join()` copy-> `<Thread>.join();` Waits for this thread to die. Throws: `InterruptedException` - if another thread has interrupted the current thread. The interrupted status of the current thread is cleared when this exception is thrown.
`void`	join(long millis) copy-> `.join( )` copy-> `<Thread>.join(<long millis>);` Waits at most `millis` milliseconds for this thread to die. A timeout of `0` means to wait forever. Parameters: `millis` - the time to wait in milliseconds. Throws: `InterruptedException` - if another thread has interrupted the current thread. The interrupted status of the current thread is cleared when this exception is thrown.
`void`	join(long millis, int nanos) copy-> `.join(, )` copy-> `<Thread>.join(<long millis>, <int nanos>);` Waits at most `millis` milliseconds plus `nanos` nanoseconds for this thread to die. Parameters: `millis` - the time to wait in milliseconds. `nanos` - 0-999999 additional nanoseconds to wait. Throws: `IllegalArgumentException` - if the value of millis is negative the value of nanos is not in the range 0-999999. `InterruptedException` - if another thread has interrupted the current thread. The interrupted status of the current thread is cleared when this exception is thrown.
`void`	resume() copy-> `.resume()` copy-> `<Thread>.resume();` Deprecated. This method exists solely for use with `suspend()`, which has been deprecated because it is deadlock-prone. For more information, see Why are Thread.stop, Thread.suspend and Thread.resume Deprecated?. Resumes a suspended thread. First, the `checkAccess` method of this thread is called with no arguments. This may result in throwing a `SecurityException` (in the current thread). If the thread is alive but suspended, it is resumed and is permitted to make progress in its execution. Throws: `SecurityException` - if the current thread cannot modify this thread. See Also: `checkAccess()`, `suspend()`
`void`	run() copy-> `.run()` copy-> `<Thread>.run();` If this thread was constructed using a separate `Runnable` run object, then that `Runnable` object's `run` method is called; otherwise, this method does nothing and returns. Subclasses of `Thread` should override this method. Specified by: `run` in interface `Runnable` See Also: `start()`, `stop()`, `Thread(java.lang.ThreadGroup, java.lang.Runnable, java.lang.String)`, `Runnable.run()`
`void`	setContextClassLoader(ClassLoader cl) copy-> `.setContextClassLoader( )` copy-> `<Thread>.setContextClassLoader(<ClassLoader cl>);` Sets the context ClassLoader for this Thread. The context ClassLoader can be set when a thread is created, and allows the creator of the thread to provide the appropriate class loader to code running in the thread when loading classes and resources. First, if there is a security manager, its `checkPermission` method is called with a `RuntimePermission("setContextClassLoader")` permission to see if it's ok to set the context ClassLoader.. Parameters: `cl` - the context ClassLoader for this Thread Throws: `SecurityException` - if the current thread cannot set the context ClassLoader. Since: 1.2 See Also: `getContextClassLoader()`, `SecurityManager.checkPermission(java.security.Permission)`, `RuntimePermission`
`void`	setDaemon(boolean on) copy-> `.setDaemon( )` copy-> `<Thread>.setDaemon(<boolean on>);` Marks this thread as either a daemon thread or a user thread. The Java Virtual Machine exits when the only threads running are all daemon threads. This method must be called before the thread is started. This method first calls the `checkAccess` method of this thread with no arguments. This may result in throwing a `SecurityException` (in the current thread). Parameters: `on` - if `true`, marks this thread as a daemon thread. Throws: `IllegalThreadStateException` - if this thread is active. `SecurityException` - if the current thread cannot modify this thread. See Also: `isDaemon()`, `checkAccess()`
`void`	setName(String name) copy-> `.setName( )` copy-> `<Thread>.setName(<String name>);` Changes the name of this thread to be equal to the argument `name`. First the `checkAccess` method of this thread is called with no arguments. This may result in throwing a `SecurityException`. Parameters: `name` - the new name for this thread. Throws: `SecurityException` - if the current thread cannot modify this thread. See Also: `getName()`, `checkAccess()`, `getName()`
`void`	setPriority(int newPriority) copy-> `.setPriority( )` copy-> `<Thread>.setPriority(<int newPriority>);` Changes the priority of this thread. First the `checkAccess` method of this thread is called with no arguments. This may result in throwing a `SecurityException`. Otherwise, the priority of this thread is set to the smaller of the specified `newPriority` and the maximum permitted priority of the thread's thread group. Parameters: `newPriority` - priority to set this thread to Throws: `IllegalArgumentException` - If the priority is not in the range `MIN_PRIORITY` to `MAX_PRIORITY`. `SecurityException` - if the current thread cannot modify this thread. See Also: `getPriority()`, `checkAccess()`, `getPriority()`, `getThreadGroup()`, `MAX_PRIORITY`, `MIN_PRIORITY`, `ThreadGroup.getMaxPriority()`
`static void`	sleep(long millis) copy-> `Thread.sleep( )` copy-> `Thread.sleep(<long millis>);` Causes the currently executing thread to sleep (temporarily cease execution) for the specified number of milliseconds. The thread does not lose ownership of any monitors. Parameters: `millis` - the length of time to sleep in milliseconds. Throws: `InterruptedException` - if another thread has interrupted the current thread. The interrupted status of the current thread is cleared when this exception is thrown. See Also: `Object.notify()`
`static void`	sleep(long millis, int nanos) copy-> `Thread.sleep(, )` copy-> `Thread.sleep(<long millis>, <int nanos>);` Causes the currently executing thread to sleep (cease execution) for the specified number of milliseconds plus the specified number of nanoseconds. The thread does not lose ownership of any monitors. Parameters: `millis` - the length of time to sleep in milliseconds. `nanos` - 0-999999 additional nanoseconds to sleep. Throws: `IllegalArgumentException` - if the value of millis is negative or the value of nanos is not in the range 0-999999. `InterruptedException` - if another thread has interrupted the current thread. The interrupted status of the current thread is cleared when this exception is thrown. See Also: `Object.notify()`
`void`	start() copy-> `.start()` copy-> `<Thread>.start();` Causes this thread to begin execution; the Java Virtual Machine calls the `run` method of this thread. The result is that two threads are running concurrently: the current thread (which returns from the call to the `start` method) and the other thread (which executes its `run` method). Throws: `IllegalThreadStateException` - if the thread was already started. See Also: `run()`, `stop()`
`void`	stop() copy-> `.stop()` copy-> `<Thread>.stop();` Deprecated. This method is inherently unsafe. Stopping a thread with Thread.stop causes it to unlock all of the monitors that it has locked (as a natural consequence of the unchecked `ThreadDeath` exception propagating up the stack). If any of the objects previously protected by these monitors were in an inconsistent state, the damaged objects become visible to other threads, potentially resulting in arbitrary behavior. Many uses of `stop` should be replaced by code that simply modifies some variable to indicate that the target thread should stop running. The target thread should check this variable regularly, and return from its run method in an orderly fashion if the variable indicates that it is to stop running. If the target thread waits for long periods (on a condition variable, for example), the `interrupt` method should be used to interrupt the wait. For more information, see Why are Thread.stop, Thread.suspend and Thread.resume Deprecated?. Forces the thread to stop executing. If there is a security manager installed, its `checkAccess` method is called with `this` as its argument. This may result in a `SecurityException` being raised (in the current thread). If this thread is different from the current thread (that is, the current thread is trying to stop a thread other than itself), the security manager's `checkPermission` method (with a `RuntimePermission("stopThread")` argument) is called in addition. Again, this may result in throwing a `SecurityException` (in the current thread). The thread represented by this thread is forced to stop whatever it is doing abnormally and to throw a newly created `ThreadDeath` object as an exception. It is permitted to stop a thread that has not yet been started. If the thread is eventually started, it immediately terminates. An application should not normally try to catch `ThreadDeath` unless it must do some extraordinary cleanup operation (note that the throwing of `ThreadDeath` causes `finally` clauses of `try` statements to be executed before the thread officially dies). If a `catch` clause catches a `ThreadDeath` object, it is important to rethrow the object so that the thread actually dies. The top-level error handler that reacts to otherwise uncaught exceptions does not print out a message or otherwise notify the application if the uncaught exception is an instance of `ThreadDeath`. Throws: `SecurityException` - if the current thread cannot modify this thread. See Also: `interrupt()`, `checkAccess()`, `run()`, `start()`, `ThreadDeath`, `ThreadGroup.uncaughtException(java.lang.Thread, java.lang.Throwable)`, `SecurityManager.checkAccess(Thread)`, `SecurityManager.checkPermission(java.security.Permission)`
`void`	stop(Throwable obj) copy-> `.stop( )` copy-> `<Thread>.stop(<Throwable obj>);` Deprecated. This method is inherently unsafe. See `stop()` (with no arguments) for details. An additional danger of this method is that it may be used to generate exceptions that the target thread is unprepared to handle (including checked exceptions that the thread could not possibly throw, were it not for this method). For more information, see Why are Thread.stop, Thread.suspend and Thread.resume Deprecated?. Forces the thread to stop executing. If there is a security manager installed, the `checkAccess` method of this thread is called, which may result in a `SecurityException` being raised (in the current thread). If this thread is different from the current thread (that is, the current thread is trying to stop a thread other than itself) or `obj` is not an instance of `ThreadDeath`, the security manager's `checkPermission` method (with the `RuntimePermission("stopThread")` argument) is called in addition. Again, this may result in throwing a `SecurityException` (in the current thread). If the argument `obj` is null, a `NullPointerException` is thrown (in the current thread). The thread represented by this thread is forced to complete whatever it is doing abnormally and to throw the `Throwable` object `obj` as an exception. This is an unusual action to take; normally, the `stop` method that takes no arguments should be used. It is permitted to stop a thread that has not yet been started. If the thread is eventually started, it immediately terminates. Parameters: `obj` - the Throwable object to be thrown. Throws: `SecurityException` - if the current thread cannot modify this thread. See Also: `interrupt()`, `checkAccess()`, `run()`, `start()`, `stop()`, `SecurityManager.checkAccess(Thread)`, `SecurityManager.checkPermission(java.security.Permission)`
`void`	suspend() copy-> `.suspend()` copy-> `<Thread>.suspend();` Deprecated. This method has been deprecated, as it is inherently deadlock-prone. If the target thread holds a lock on the monitor protecting a critical system resource when it is suspended, no thread can access this resource until the target thread is resumed. If the thread that would resume the target thread attempts to lock this monitor prior to calling `resume`, deadlock results. Such deadlocks typically manifest themselves as "frozen" processes. For more information, see Why are Thread.stop, Thread.suspend and Thread.resume Deprecated?. Suspends this thread. First, the `checkAccess` method of this thread is called with no arguments. This may result in throwing a `SecurityException` (in the current thread). If the thread is alive, it is suspended and makes no further progress unless and until it is resumed. Throws: `SecurityException` - if the current thread cannot modify this thread. See Also: `checkAccess()`
`String`	toString() copy-> `.toString()` copy-> `<String var>=<Thread>.toString();` Returns a string representation of this thread, including the thread's name, priority, and thread group. Overrides: `toString` in class `Object` Returns: a string representation of this thread.
`static void`	yield() copy-> `Thread.yield()` copy-> `Thread.yield();` Causes the currently executing thread object to temporarily pause and allow other threads to execute.

java.lang Class Thread

java.lang
Class Thread