Java command line could not find or load main class

Question

I have been trying to run any .class file from the command line, and I keep getting this error. After trying to figure out the problem on my own all night, i'm officially stumped.

I'm on linux, and I use eclipse usually so my .java file and .class file are in two different locations.

Heres classpath....

%> echo $CLASSPATH
/home/mike/Documents/java

Heres one of my .class directories...

/home/mike/Documents/java/homework/bin/src

Heres the corresponding .java directory...

/home/mike/Documents/java/homework/src/src

Heres what I enter in bash...

[ mike (23:31:16): ~] $ >java homework.bin.src.EulerMath

OR

[ mike (23:32:41): ~/Documents/java] $ >java -cp . homework.bin.src.EulerMath

OR

[ mike (23:34:08): ~/Documents/java/homework/bin/src] $ >java -cp . EulerMath

All give me the same error. Obviously im trying to run EulerMath.class, which is within the package src. This compiles and runs fine within eclipse, and I have a similar issue with every other program i try to run from the command line. I can compile the .java file with javac but when trying to run the new .class file i get this error. Id appreciate any help

• MadProgrammer: Have you compiled the .java file?
• Elliott Frisch: Is EulerMath in a package (what is the first non-commented line of EulerMath)? The package name is part of the class in Java. The directory structure is not meaningless.
• mike: @MadProgrammer yes, using both javac command and eclipse ElliotFrisch yes, as stated above it is in the src package and that is included in my commands

Answer 1

Modify your CLASSPATH like

export CLASSPATH="$HOME/Documents/java/homework/bin"

then you can run it without a -cp command line like

java src.EulerMath

Without setting the CLASSPATH (or if you want to override the set CLASSPATH) you can do

java -cp $HOME/Documents/java/homework/bin src.EulerMath

But src.EulerMath is the name of your class. Alternatively, you can package it in a jar file with some meta-information (basically a Main-Class) and run it with java -jar <jarfile.jar>

• mike: i have already modified CLASSPATH in ~/.bashrc, where i modified my PATH as well. The CLASSPATH var reflects this change.
• Elliott Frisch: @mike Note that the CLASSPATH I have provided here matches where you said your classes are (namely src/EulerMath.class is in /home/mike/Documents/java/homework/bin). Your question says you set it to /home/mike/Documents/java/homework/bin/src; note the difference.

Answer 2

I've managed to find the class (Note: not run it yet, i got a new error but thats a different story). Hopefully this helps someone else

Somewhere along these steps it fixed itself:

• make sure CLASSPATH is correct
• install javac
• use javac on file
• reboot computer

should work now