It appears the -subpackages option causes Javadoc to hang (sit there with
no output) in at least one case where the top level subpackage is name "pkg".
Simply changing the top-level name to "pkgs" or "pk" or "a" prevents it
from hanging. The hang occurs with 1.4.1 and build b05 of 1.4.2.

Example that fails:

=================>[doog]/home/dkramer/javadoc/1.4
% find src-subpackageshangs -name \* -print
src-subpackageshangs
src-subpackageshangs/pkg
src-subpackageshangs/pkg/b
src-subpackageshangs/pkg/b/T.java

=================>[doog]/home/dkramer/javadoc/1.4
% more src-subpackageshangs/pkg/b/T.java
package pkg.b;

public class T {}

=================>[doog]/home/dkramer/javadoc/1.4
% more run-subpackageshangs
/java/re/jdk/1.4.1/latest/binaries/solaris-sparc/bin/javadoc -J-Xmx20M -d html-subpackageshangs -sourcepath src-subpackageshangs -subpackages pkg

=================>[doog]/home/dkramer/javadoc/1.4
% run-subpackageshangs
^C

Changing the top-level directory to anything else does not hang:

=================>[doog]/home/dkramer/javadoc/1.4
% mv src-subpackageshangs/pkg src-subpackageshangs/pkgs

=================>[doog]/home/dkramer/javadoc/1.4
% more run-subpackageshangs
/java/re/jdk/1.4.1/latest/binaries/solaris-sparc/bin/javadoc -J-Xmx20M -d html-subpackageshangs -sourcepath src-subpackageshangs -subpackages pkgs

=================>[doog]/home/dkramer/javadoc/1.4
% run-subpackageshangs
Loading source files for package pkgs.b...
Constructing Javadoc information...
javadoc: warning - No source files for package pkgs.b
Standard Doclet version 1.4.1

Generating html-subpackageshangs/constant-values.html...
javadoc: No public or protected classes found to document.
1 error
1 warning