FileLock

public abstract class FileLock
extends Object implements AutoCloseable

A token representing a lock on a region of a file.

A file-lock object is created each time a lock is acquired on a file via one of the lock or tryLock methods of the FileChannel class, or the lock or tryLock methods of the AsynchronousFileChannel class.

A file-lock object is initially valid. It remains valid until the lock is released by invoking the release method, by closing the channel that was used to acquire it, or by the termination of the Java virtual machine, whichever comes first. The validity of a lock may be tested by invoking its isValid method.

A file lock is either exclusive or shared. A shared lock prevents other concurrently-running programs from acquiring an overlapping exclusive lock, but does allow them to acquire overlapping shared locks. An exclusive lock prevents other programs from acquiring an overlapping lock of either type. Once it is released, a lock has no further effect on the locks that may be acquired by other programs.

Whether a lock is exclusive or shared