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VOOZH | about |
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VOOZH | about |
A thread is the smallest unit of execution within a program, allowing multiple tasks to run concurrently. In Java, threads help improve performance by enabling parallel execution.
Thread class or Runnable interface start() which internally calls run()Note: Every class that is used as a thread must implement Runnable interface and override its run method.
public class Thread extends Object implements Runnable
| Constructor | Action Performed |
|---|---|
| Thread() | Allocates a new Thread object. |
| Thread(Runnable target) | Allocates a new Thread object. |
| Thread(Runnable target, String name) | Allocates a new Thread object. |
| Thread(String name) | Allocates a new Thread object. |
| Thread(ThreadGroup group, Runnable target) | Allocates a new Thread object. |
| Thread(ThreadGroup group, Runnable target, String name) | Allocates a new Thread object so that it has targeted as its run object, has the specified name as its name, and belongs to the thread group referred to by a group. |
| Thread(ThreadGroup group, Runnable target, String name, long stackSize) | Allocates a new Thread object so that it has targeted as its run object, has the specified name as its name, and belongs to the thread group referred to by group, and has the specified stack size. |
| Thread(ThreadGroup group, String name) | Allocates a new Thread object. |
Example: Java program to demonstrate usage of Thread class
Thread 1 - Count : 0
Thread 2 - Count : 0
Thread 1 - Count : 1
Thread 2 - Count : 1
Thread 1 - Count : 2
Thread 2 - Count : 2
Thread 1 - Count : 3
Thread 2 - Count : 3
Thread 2 - Count : 4
Thread 1 - Count : 4
Note: Execution of the thread is not according to the sequence, it can be executed in any sequence Thread 1 then Thread 2 , or Thread 2 then Thread 1.
| Methods | Action Performed |
|---|---|
| activeCount() | Returns an estimate of the number of active threads in the current thread's thread group and its subgroups |
| checkAccess() | Determines if the currently running thread has permission to modify this thread |
| clone() | Throws CloneNotSupportedException as a Thread can not be meaningfully cloned |
| currentThread() | Returns a reference to the currently executing thread object |
| dumpStack() | Prints a stack trace of the current thread to the standard error stream |
| enumerate(Thread[] tarray) | Copies into the specified array every active thread in the current thread's thread group and its subgroups |
| getAllStackTraces() | Returns a map of stack traces for all live threads |
| getContextClassLoader() | Returns the context ClassLoader for this Thread |
| getDefaultUncaughtExceptionHandler() | Returns the default handler invoked when a thread abruptly terminates due to an uncaught exception |
| getId() | Returns the identifier of this Thread |
| getName() | Returns this thread's name |
| getPriority() | Returns this thread's priority |
| getStackTrace() | Returns an array of stack trace elements representing the stack dump of this thread |
| getState() | Returns the state of this thread |
| getThreadGroup() | Returns the thread group to which this thread belongs |
| getUncaughtExceptionHandler() | Returns the handler invoked when this thread abruptly terminates due to an uncaught exception |
| holdsLock(Object obj) | Returns true if and only if the current thread holds the monitor lock on the specified object |
| interrupt() | Interrupts this thread |
| interrupted() | Tests whether the current thread has been interrupted |
| isAlive() | Tests if this thread is alive |
| isDaemon() | Tests if this thread is a daemon thread |
| isInterrupted() | Tests whether this thread has been interrupted |
| join() | Waits for this thread to die |
| join(long millis) | Waits at most millis milliseconds for this thread to die |
| 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 |
| setContextClassLoader(ClassLoader cl) | Sets the context ClassLoader for this Thread |
| setDaemon(boolean on) | Marks this thread as either a daemon thread or a user thread |
| setDefaultUncaughtExceptionHandler( Thread.UncaughtExceptionHandler eh) | Set the default handler invoked when a thread abruptly terminates due to an uncaught exception, and no other handler has been defined for that thread |
| setName(String name) | Changes the name of this thread to be equal to the argument name. |
| setUncaughtExceptionHandler( Thread.UncaughtExceptionHandler eh) | Set the handler invoked when this thread abruptly terminates due to an uncaught exception |
| setPriority(int newPriority) | Changes the priority of this thread |
| sleep(long millis) | Causes the currently executing thread to sleep (temporarily cease execution) for the specified number of milliseconds, subject to the precision and accuracy of system timers and schedulers |
| start() | Causes this thread to begin execution; the Java Virtual Machine calls the run method of this thread |
| toString() | Returns a string representation of this thread, including the thread's name, priority, and thread group |
| yield() | A hint to the scheduler that the current thread is willing to yield its current use of a processor |