Re: importing external class from inside package

Lew <>
Sun, 17 Dec 2006 11:50:01 -0500
Tor Iver Wilhelmsen wrote:

You probably need to add "-cl?asspath ." to the command in order to
tell it the local dir should be searched; the current dir is not in
the default classpath.

Some minor points in addition to the above advice.

Uncle Sam wrote:

files and in a package 'Otherwinter'.

Exactly correct from the language perspective. However, there are a set of
conventions proffered by Sun:


a few of which have widely accepted variants (opening brace placement on a new

In particular,


discusses package and other name conventions. Common usage extends the package
name convention such that all package name components comprise lower-case
characters. Sun themselves suggest merely that, after the initial top-level
domain prefix in lower-case letters, "[s]ubsequent components of the package
name vary according to an organization's own internal naming conventions".

If your software goes to public use, prefix your package names with your
top-level domain (com, gov, org, edu) and your organization's domain name
(affiliatedamalgamates, mit), thus:


The classpath includes the directory '/users/prakhar/'.

This is the key fact.

"javac *.java".

I have observed that javac is a tad lenient about directory level; it seems to
suss out the package declarations and forgive you for being rooted at the
wrong level.

The java executor is not so kind.

I suspect rmic is likely to be strict also.

The safest is just to include the classpath at every step, and ensure that it
contains the root of the various package trees. The current directory, ".", is
perfectly valid as a classpath element.

   |--- org/ --- apache/ --- junit/ ---
   | | --- log4j/ ---
   |--- com/ --- affiliatedamalgamates/ --- Otherwinter/ ---

Another tip: use separate directory trees for the source and the .class files.
Yet another tip: Use Ant to automate your build and distribution.

 >> Now I have to compile the classes OtherA and OtherB

with the RMI compiler 'rmic'. So I go to the Otherwinter directory and

Go to the root directory above Otherwinter/ instead.
Better yet, don't change directories at all.

give the command "rmic Otherwinter.OtherA" and "rmic
Otherwinter.OtherB". This works perfectly fine in Linux.

Perhaps rmic is more forgiving than I guessed.

It's safer to root your command line at a parent directory, safer still to
root your commands at a project directory and let a script sort out the
relative path roots, safest of all to use Ant or one of the build platforms
out there.

Let's say your project root directory is $PROJECT, with subdirectories 'src/',
'build/' and 'build/classes/'.

$ javac -deprecation -d $PROJECT/build/classes $PROJECT/src/com/affiliatedamalgamates/otherwinter/ $PROJECT/src/com/affiliatedamalgamates/winter/
$ java -cp $PROJECT/build/classes winter.A

- Lew

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