Re: [Jython-users] jython on WinCE/iPaq update

[<bc...@wo...>]

[Brian Zhou]

>Hi all,
>
>About two months ago I experimented with jython on WinCE/iPaq and had some
>success, now VAME (IBM visual age micro edition) has released 1.4 (== 1.3.0
>jvm), so I tried the new version.
>
>Good news is I don't have to copy Sun's rt.jar, and pystone shows an
>improvement from 48 to 52. But adding \vame1.4\lib\jclMax\classes.zip to the
>classpath option does not work, I have to work around by using a 9M
>extracted .class tree.
>
>Here's the updated instruction:
>...

Sounds like a good candidate for a faq entry:

  2.7 How do I install jython on my iPAQ

>
>Here's the part I hope someone can give me some insight, I want to know why
>classes.zip cannot be in classpath:
>
>1. If I leave the classpath as "-cp:\jython-2.1a1\jython.jar", I can launch
>jython fine, do all the python stuff, while "import java" shows "no module
>named java"
>2. If I use "-cp:\vame1.4\lib\jclMax\classes.zip;\jython-2.1a1\jython.jar",
>I got error message:
>*sys-package-mgr*: processing new jar, '\vame1.4\lib\jclMax\classes.zip'
>java.lang.IndexOutOfBoundsException
>
>Stack trace:
>   java/lang/Throwable.<init>()V
>   java/lang/Throwable.<init>(Ljava/lang/String;)V
>   java/lang/IndexOutOfBoundsException.<init>(Ljava/lang/String;)V
>   java/util/zip/ZipInputStream.read([BII)I
>   java/util/zip/ZipInputStream.skip(J)J
>   java/io/DataInputStream.skipBytes(I)I
>   org/python/core/PackageManager.checkAccess(Ljava/io/InputStream;)I
>   ...

I find the stacktrace curious. Totally unrelated to the problem you are
having, but when a skip() call can cause a IOOB (perhaps because a
over/underflow of the temporary buffer allocated by skip) then
ZipInputStream are having serious internal problems. Perhaps OTI can be
convinced to take a closer look at the IOOB exception.

>3. As mentioned, extract classes.zip to directory and add directory to -cp
>works fine.
>4. I also tried to jar classes/ directory into a classes.jar but that caused
>jython to complain "skip bad jar"
>
>Anyone has any idea the cause, or what to do further?

As the OTI guy said, putting classes.zip on -cp isn't the solution (even
if it didn't throw a IOOB).

I have made a very experimental feature that allow a tool (running under
java2 on windows or unix) to pre-index a zip/jar file. The pre-index is
then stored inside the zip file.

If you want to try it out (and I really think you should because it
fixes the problems you are having with this) you will have to apply a
patch to SysPackageManager.java and install a new source file in
org/python/util/jythonjar.java.

>  http://sourceforge.net/tracker/index.php?func=detail&aid=454329&group_id=12867&atid=312867

When you have compiled the changes to jython, you run the indexer tool
like this:

 java org.python.util.jythonjar -usecp -cp classes.zip jython.jar

After this the jython.jar file is updated with a lot of entries called

  META-INF/JYTHON-PACKAGES-java
  META-INF/JYTHON-PACKAGES-java.lang
  ...

These entries will be used when the cache dir doesn't contain entries
for the packages. As a result classes.zip doesn't need to be on the -cp.


regards,
finn