Re: javac classpath; where to compile from?

I would like to compile and execute (run) without changing directories.
Currently, however, I get the following error:

thufir@arrakis:~/java$
thufir@arrakis:~/java$ javac -cp src -d /home/thufir/java/build/ src/com/
web_tomorrow/CPTest2.java
thufir@arrakis:~/java$
thufir@arrakis:~/java$ java build.com.web_tomorrow.CPTest
Exception in thread "main" java.lang.NoClassDefFoundError: build/com/
web_tomorrow/CPTest
thufir@arrakis:~/java$
thufir@arrakis:~/java$

To get good output, only this seems to work:

thufir@arrakis:~/java/src$
thufir@arrakis:~/java/src$ javac -cp . -d /home/thufir/java/build/ com/
web_tomorrow/CPTest2.java
thufir@arrakis:~/java/src$
thufir@arrakis:~/java/src$ cd ..
thufir@arrakis:~/java$
thufir@arrakis:~/java$ cd build/
thufir@arrakis:~/java/build$
thufir@arrakis:~/java/build$ java com.web_tomorrow.CPTest2
Run CPTest2.main()
thufir@arrakis:~/java/build$
thufir@arrakis:~/java/build$

how can I do this without changing directories?

thanks,

Thufir