You must do this if you experience an issue where "javac" cannot find your classes, even when you are in the same directory as them.  One such message would be to the order of "Java class definition not found exception".

Modifying your CLASSPATH statement is exactly like modifying your PATH statement.  For detailed descriptions and illustrations of how to do the following, please refer to the "Modifying your PATH statement" section of "Install JDK".

1. Open up System Editor with Start/Run : "sysedit".

2. Look for a line that says "CLASSPATH=", if there is none move to step 3.  If it exists, change it to reflect the location of the classes.zip file in your JDK installation PLUS the local directory, '.' .  The classes.zip file is always in the lib directory of the JDK.  A typical location is:

CLASSPATH=c:\jdk1.2.1\lib\classes.zip;.

3. If there is no CLASSPATH line, add a line that says "CLASSPATH=" and then the location of the classes.zip file in the JDK installation PLUS the local directory, '.'.  It is always in the lib directory of the JDK.  So a typical line would be:

CLASSPATH=c:\jdk1.2.1\lib\classpath.zip; .

5. Close the System Editor, and restart the computer.