protected FileLock (FileChannel channel, long position, long size, boolean shared)

Initializes a new instance of this class.

channel     The file channel upon whose file this lock is held
position     The position within the file at which the locked region starts; must be non-negative
size     The size of the locked region; must be non-negative, and the sum position +  size must be non-negative
shared     true if this lock is shared, false if it is exclusive

IllegalArgumentException     If the preconditions on the parameters do not hold