ubuntu java classpath,在Ubuntu中正确设置java classpath和java_home

I am getting the error

Exception in thread "main" java.lang.NoClassDefFoundError:

When I try and run a compiled class on Ubuntu. I am using a very simple Helloworld example, and the millions of responses which already exist on the internet suggest that my CLASSPATH and JAVA_HOME variables have been incorrectly set.

However, I have edited the etc/environment to the correct folders as well as the current folder:

PATH=".:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games"

JAVA_HOME="/usr/lib/jvm/java-1.5.0-sun/"

CLASSPATH=".:/usr/lib/jvm/java-1.5.0-sun/lib"

and they appear when I type the set command. In any case, even when I set the classpath manually using

sudo java -cp . myfirstjavaprog.class

I get the same error. Where else should I look? This must be a configuration problem.

Many thanks

解决方案

You want to drop the .class from the end. Just type...

java -cp . myfirstjavaprog