This isn't strictly a "javac" issue, but it is caused by compiler tools code
used by the tools with which the bug is an issue, so I figured I would put it
in the compiler category for now.

The problem is that if you use rmic or javap with a class name that, with
anything that might qualify as a package qualifier stripped off, contains
spaces in other than the first position, a CompilerError is thrown. For
example:

[terrier]<peter> 41 % javap "a b"
sun.tools.java.CompilerError: mangle a b
        at sun.tools.java.Type.mangleInnerType(Type.java)
        at sun.tools.java.Type.tClass(Type.java)
        at sun.tools.util.LoadEnvironment.classExists(LoadEnvironment.java)
        at sun.tools.javap.JavaP.displayResults(JavaP.java)
        at sun.tools.javap.JavaP.perform(JavaP.java)
        at sun.tools.javap.JavaP.main(JavaP.java)

This only happens with the most recent (8/20) putback of changes to the
JDK 1.2 beta workspace (it did not occur with JDK 1.2I, at least as long as
you use the command line wrapper). It was caused by the fix to 4053337,
where the wrapper scripts for these tools no longer convert single arguments
with spaces into separate arguments to the tool (which was happening
accidentally).

The cause of this bug is that Type.mangleInnerType is called because when
looking for the binary class file, the mangled representation of inner class
names must be used in file names. This strips off package qualifiers,
replaces ". " with "$", but then if Identifier.isInner() return true, a
CompilerError will get thrown. But Identifier.isInner() will return true
if indexOf(' ') > 0, so if there are any extraneous spaces in the identifier
after the first position, it will still return true.