Java Reference
In-Depth Information
Other Reasons It Might Not Work
Here are some other things that might go wrong even if the
PATH
is set correctly:
Make sure you are in the right directory; type
ls
and check that the file
CreeperTest.java
is right there.
Make sure you're typing
javacCreeperTest.java
(with the
.java
part). Otherwise you
might see a truly confusing error message like this one:
error: Class names, 'CreeperTest', are only accepted if
annotation processing is explicitly requested
If the
javac
command reports some kind of “syntax” or “not found” or “not
defined” error, that means it doesn't understand the text in the
CreeperTest.java
file, so you may have mistyped something. These kinds of errors might look
something like this:
CreeperTest.java:1: class, interface, or enum expected
Or you might see some other error message. The number in between the
colons (
:1:
) is the line number where the typo is located.
If you can't find the typo, grab a fresh copy of the file from this topic's down-
loaded source code, at
code/install/CreeperTest.java
, and try that.
If the
java
command can't find
CreeperTest.class
, make sure the
javac
command
ran okay and that it produced a
.class
file successfully. You should be in that
same directory when running
java
.
If you see this error
Exception in thread "main" java.lang.NoClassDefFoundError: CreeperTest/class
you may have accidentally typed
javaCreeperTest.class
(with the
.class
part at the
end) instead of
java CreeperTest
(no suffix). To recap, these are the commands
to compile and then run:
$
javac CreeperTest.java
$
java CreeperTest
That is, you must specify the
.java
suffix when compiling, but do not type in
the
.class
part when running with
java
.
Also, check to see if there's a setting for
CLASSPATH
(which is just like
PATH
, but
for Java classes).
$
echo $CLASSPATH
$
