sleep() is a native method, it’s IMPLEMENTATION is provided by JVM.
10 salient FEATURES of sleep() method >
•Definition : sleep() METHODS causes current thread to sleep for specified number of milliseconds (i.e. TIME passed in sleep method as parameter). Ex- Thread.sleep(10) causes currently executing thread to sleep for 10 millisec.
•Thread state : when sleep() is called on thread it goes from running to waiting state and can return to runnable state when sleep time is up.
•Exception : sleep() method must catch or throw compile time exception i.e. InterruptedException.
•Waiting time : sleep() method have got few options.
1.sleep(long millis) - Causes the currently executing thread to sleep for the specified number of milliseconds
public static native VOID sleep(long millis) throws InterruptedException;
1.sleep(long millis, int nanos) - Causes the currently executing thread to sleep for the specified number of milliseconds plus the specified number of nanoseconds.
public static native void sleep(long millis,int nanos) throws InterruptedException;
•static method : sleep()is a static method, causes the currently executing thread to sleep for the specified number of milliseconds.
•Belongs to which class :sleep() method belongs to java.lang.Thread class.
•synchronized block : thread need not to to acquire object lock before calling sleep()method i.e. sleep() method can be called from outside synchronized block.

sleep() is a native method, it’s implementation is provided by JVM.
10 salient features of sleep() method >
•Definition : sleep() methods causes current thread to sleep for specified number of milliseconds (i.e. time passed in sleep method as parameter). Ex- Thread.sleep(10) causes currently executing thread to sleep for 10 millisec.
•Thread state : when sleep() is called on thread it goes from running to waiting state and can return to runnable state when sleep time is up.
•Exception : sleep() method must catch or throw compile time exception i.e. InterruptedException.
•Waiting time : sleep() method have got few options.
1.sleep(long millis) - Causes the currently executing thread to sleep for the specified number of milliseconds
public static native void sleep(long millis) throws InterruptedException;
1.sleep(long millis, int nanos) - Causes the currently executing thread to sleep for the specified number of milliseconds plus the specified number of nanoseconds.
public static native void sleep(long millis,int nanos) throws InterruptedException;
•static method : sleep()is a static method, causes the currently executing thread to sleep for the specified number of milliseconds.
•Belongs to which class :sleep() method belongs to java.lang.Thread class.
•synchronized block : thread need not to to acquire object lock before calling sleep()method i.e. sleep() method can be called from outside synchronized block.