Your PATH is wrong, or it contains a bin directory from an obsolete or largely uninstalled JDK, or your CLASSPATH points to an obsolete JDK, or possibly a JRE. If either of the latter, remove that element from the PATH or CLASSPATH.
What do I actually need for the CLASSPATH if I need anything.
There's no need for a CLASSPATH setting other than '.' as far as Java itself is concerned.