Re: Novice linux java coder needs help getting progs to run

Tom Anderson <>
Tue, 25 Aug 2009 14:16:39 +0100
On Sat, 22 Aug 2009, Arne Vajh?j wrote:

Tom Anderson wrote:

On Wed, 19 Aug 2009, wrote:

On Tue, 18 Aug 2009 20:49:14 -0700
Roedy Green <> wrote:

On 18 Aug 2009 11:20:24 +0200, I V <> wrote, quoted
or indirectly quoted someone who said :

java hello

or better still
java Hello

Class names should start with a capital letter as should the file it lives in.

Why? It looks daft and is more hassle to type

Them's the rules. In practice, you don't run real apps that way, you run
then as executable JARs:

java -jar hello.jar

Maybe I am bit weird but I would use:

java -cp hello.jar HelloWorld

for command line - I consider the executable jar feature to
be mostly a GUI double click feature.

I think of it as an application packaging feature. I guess it's largely a
matter of taste. Although:

  When you use this option, the JAR file is the source of all user
  classes, and other user class path settings are ignored.

Which you might think was a good thing from a hygeine perspective.

Also, i thought that java would only pay attention to the Class-Path
entries in the manifest in -jar mode, but perhaps i'm imagining that.

on systems which are case sensitive (ie almost all of them except

It makes no difference if the system is case sensitive or not. If it is
case sensitive, it will say 'file not found' if the case is wrong, and if
it isn't, it will say 'class format error', because the file hello.class
contains a class called Hello, and java is case-sensitive internally.


java.lang.NoClassDefFoundError: hello (wrong name: Hello)

Oh, cool. I remember seeing a much less helpful message in the past,
although i confess my memory may be faulty.


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