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From: Eric Sosman <esosman@comcast-dot-net.invalid>
Newsgroups: comp.lang.java.programmer
Subject: Re: java Environment in Manjaro Linux
Date: Fri, 22 Jan 2016 11:16:10 -0500
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On 1/22/2016 10:37 AM, ruben wrote:
> I'm testing the java developers environment and its not working as I
> expected
>
> [ruben@localhost cs664s16]$ cat ./helloworld.java
> public class helloworld {
>     public static void main(String[] args) {
>           System.out.println("Bonjour le monde !");
>   }
>
> }
>
>
> [ruben@localhost cs664s16]$ echo $CLASSPATH
> /home/ruben/GNUstep/Library/Libraries/Java:/root/GNUstep/Library/
> Libraries/Java:/usr/lib/GNUstep/Libraries/Java:.:./
>
>
> [ruben@localhost cs664s16]$ java ./helloworld.java
> Error: Could not find or load main class ..helloworld.java
>
>
> this works however:
>
> [ruben@localhost cs664s16]$ java helloworld
> Bonjour le monde !
>
>
>
> So, I am completely confused.  How can it not take the specified file
> name to run?

     `helloworld.java' is a source file full of Java source code.
The corresponding class file (produced by the javac compiler) would
be `helloworld.class'.  If you're familiar with languages like C or
C++, this is similar to the distinction between `helloworld.c' and
`helloworld.o'.

     Furthermore, the java command itself doesn't want either file
name: It just wants the class name `helloworld', and it knows to
look for `helloworld.class' in "various places."  In your case it
will find `helloworld.class' as an ordinary file in one of the
directories listed in CLASSPATH, but there are other possibilities
that can be used in other setups.  It might find `helloworld.class'
as one member of a "jar file" (a specially-formatted ZIP archive),
or it might be told to load `helloworld.class' from the network,
and still other even more exotic setups can be concocted.  The
upshot, though, it that you tell Java the unadorned class name,
not the name of a file.

> Also, where is the $CLASSPATH set?  in the system /etc/profile ?  I
> should probaly add ./ to the bashrc file?

     Sorry; I have no idea what piece of script sets your CLASSPATH.

-- 
esosman@comcast-dot-net.invalid
"Don't be afraid of work. Make work afraid of you." -- TLM