When compiling the second class, you need to make sure that the classpath of SEMConnector.class is visible. If the SEMConnector.class is in the same directory as the source, try this at the command line:
set classpath=%classpath%;. javac *.java
the "." tells the compiler that everything in the current directory is in the classpath. If the SEMConnector.class is in a different directory, put that directory in the classpath, something like so:
set classpath=%classpath%;C:\ConnectorCode\classes javac *.java
Also, make sure that you put SEMConnector.class in a directory that matches your package 'com.rexam.sem.db.semDB', ie... \com\rexam\sem\db\semDB. That's basically what a package does, it specifies the directory where the class can be found.
Notice the ".;" at the beginning...since both my classes are in the same directory (and correct package structure) I shouldn't have had a problem with compilation in the first place, should I...?
If you have any thoughts on this I'd be glad to hear them, becuase although both my classes compile now, I'm still scratching my head about why the ".;" entry in my classpath seemed not to have any effect.