java run time problems

[lord bacon]

i seem to be having a problem with running java Programs from the command line, the programs (only very simple ones to see if this actually works) are compiling okay, but when i try to run them i am getting errors saying it cant find the main class, here is the output:

Exception in thread "main" java.lang.NoClassDefFoundError: Test.class
at gnu.java.lang.MainThread.run(libgcj.so.70)
Caused by: java.lang.ClassNotFoundException: Test.class not found in gnu.gcj.runtime.SystemClassLoader{urls=[file:./], parent=gnu.gcj.runtime.ExtensionClassLoader{urls=[], parent=null}}
at java.net.URLClassLoader.findClass(libgcj.so.70)
at gnu.gcj.runtime.SystemClassLoader.findClass(libgcj .so.70)
at java.lang.ClassLoader.loadClass(libgcj.so.70)
at java.lang.ClassLoader.loadClass(libgcj.so.70)
at gnu.java.lang.MainThread.run(libgcj.so.70)

the code i was attempting to run was:

public class Test
{
public static void main (String[] args)
{
System.out.println("Test Program output");
}
}


as you can see it is very simple but i cant get it to run. this used to work using the usual java SDK, but when i installed eclipse it changed somethin somewhere, and now i cant run any programs, why is this happening.

thanks Lord Bacon

[samjh]

You have GCJ set as your default Java environment.

Run this in the terminal:

sudo update-alternatives --config java
and for good measure:

sudo update-alternatives --config javac
For each one, select the Java version provided by Sun, not GCJ.

Then recompile your program.

[Tomosaur]

It looks like you're trying to run the program using 'java Test.class'. The actual command you need to type is 'java Test'. Just leave the '.class' off.

I would also suggest you drop gcj and just use Sun's java, it'll save you a lot of headaches later on (and Sun's Java is - or at least, will be soon - GPLd, so if you only want a free Java, then Sun's is just as good, or better, than gcj).

[lord bacon]

Thanks samjh, your idea worked perfectly, everythin is workin fine again. Tamosaur, yea just noticed that i had .class, but the same thing was happening with out it there.. neways, thanks heaps for the help guys..

[Ramses de Norre]

You have GCJ set as your default Java environment.

Run this in the terminal:

sudo update-alternatives --config java
and for good measure:

sudo update-alternatives --config javac
For each one, select the Java version provided by Sun, not GCJ.

Then recompile your program.

sudo update-java-alternatives -s <version> will take care of all java related packages at once (for instance also javah and javadoc and such), find out your version with the -l switch.

[samjh]

Very cool. Thanks, Ramses de Norre.