The following keywords are reserved in Java, so you must not use them as names in your programs:
abstract
assert
boolean
break
byte
case
catch
char
class
const
continue
default
do
double
else
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
You should also not attempt to use the boolean values true and false, or null as names in your programs.