how to create a new java program using CRTJVAPGM?

how do I create a java program using the CRTJVAPGM command when the .class
file does not yet exist?

using the CRTJVAPGM command to create a java program.
CRTJVAPGM CLSF('HelloWorld.class') CLASSPATH('/home/srichter')

It fails because the .class file does not exist. Only the .java file exists
at this point.

but once I create the .class file by running javac from QSH, the above
mentioned CRTJVAPGM command works.
javac helloworld.java

but specifiying the .java file on the CRTJVAPGM command does not work:
CRTJVAPGM CLSF('HelloWorld.java') CLASSPATH('/home/srichter')

I guess I can figure out the difference between a .class file and .java
file. But why does CRTJVAPGM want the .class file specified when that is
the file that is created by CRTJVAPGM?