Nicht erlaubte Bezeichner sind Java-Schlüsselwörter und Literale true, false und null.
Java Schlüsselwörter
abstract
catch
default
final
if
interface
private
static
this
void
try
boolean
char
do
finally
implements
long
protected
strictfp
throw
volatile
synchronized
brak
class
double
float
import
native
public
suer
throws
while
int package
short
byte
const else
for
instanceof
new
return
switch
transient
case
continue
goto