You can’t use keyword as identifier in your Java programs, its reserved words in Java library and used to perform an internal operation.

abstract  assert boolean break
byte case catch char
class const continue default
do double else enum
extends final finally float
for goto if implements
import instanceof int interface
long native new package
private protected public return
short static strictfp super
switch synchronized this throw
throws transient try void
volatile while  true  false

true, false and null are not reserved words but cannot be used as identifiers, because it is literals of built-in types.

error: Content is protected !!