Trouble with running java using Popen

[Edward Grefenstette]

I have a java prog I need to run at some point during the execution of
a python module.

The path to the folder containing the all the relevant java stuff
(which runs fine from the command line) is stored in pkgpath. The
relevant code is this:

Here indexpath is the path to a particular index file (usually
indexpath = "./indexfolder/fileindex"), so that effectively Popen
should be running the equivalent of the shell command:
-
java -Xmx1024m SemanticVectorsEvaluator ../indexfolder/fileindex
-
which, again, runs fine in the terminal.

However running the program returns the following error (echoed from
shell, doesn't interrupt prog):
-
Exception in thread "main" java.lang.NoClassDefFoundError:
SemanticVectorsEvaluator
-

I have no idea why this isn't working. Anyone have any suggestions as
to how I might troubleshoot this?

Best,
Edward

 

[norseman]

I have a java prog I need to run at some point during the execution of
a python module.

The path to the folder containing the all the relevant java stuff
(which runs fine from the command line) is stored in pkgpath. The
relevant code is this:


Here indexpath is the path to a particular index file (usually
indexpath = "./indexfolder/fileindex"), so that effectively Popen
should be running the equivalent of the shell command:
-
java -Xmx1024m SemanticVectorsEvaluator ../indexfolder/fileindex
-
which, again, runs fine in the terminal.

However running the program returns the following error (echoed from
shell, doesn't interrupt prog):
-
Exception in thread "main" java.lang.NoClassDefFoundError:
SemanticVectorsEvaluator
-

I have no idea why this isn't working. Anyone have any suggestions as
to how I might troubleshoot this?

Best,
Edward

=================
First glance shows you using ./ in code and ../in terminal. Might check
that first.

Second glance shows you using Popen vs popen (OK) but is that the
correct stdout? It is the CHILD's stdout that is being requested here.
(Probably what you had in mind, but ... is it?)

Third item - running from the terminal usually loads the terminal
environment. Running under program control may NOT load the environment.
This is a particular problem in Window$. Is the difference going to
effect your efforts?


As for Java specific problems (if any) I don't know. Another might.


Steve

 

[Chris Rebert]

I have a java prog I need to run at some point during the execution of
a python module.

The path to the folder containing the all the relevant java stuff
(which runs fine from the command line) is stored in pkgpath. The
relevant code is this:


Here indexpath is the path to a particular index file (usually
indexpath = "./indexfolder/fileindex"), so that effectively Popen
should be running the equivalent of the shell command:
-
java -Xmx1024m SemanticVectorsEvaluator ../indexfolder/fileindex
-
which, again, runs fine in the terminal.

However running the program returns the following error (echoed from
shell, doesn't interrupt prog):
-
Exception in thread "main" java.lang.NoClassDefFoundError:
SemanticVectorsEvaluator
-

I have no idea why this isn't working. Anyone have any suggestions as
to how I might troubleshoot this?

Have you tried?:

arglist = ["java", "-Xmx1024m", "SemanticVectorsEvaluator", "." + indexpath]
SemVectPackage = Popen(arglist, stdout=PIPE)
SemVectPackage.wait()

Cheers,
Chris

 

[Diez B. Roggisch]

I have a java prog I need to run at some point during the execution of
a python module.

The path to the folder containing the all the relevant java stuff
(which runs fine from the command line) is stored in pkgpath. The
relevant code is this:


Here indexpath is the path to a particular index file (usually
indexpath = "./indexfolder/fileindex"), so that effectively Popen
should be running the equivalent of the shell command:
-
java -Xmx1024m SemanticVectorsEvaluator ../indexfolder/fileindex
-
which, again, runs fine in the terminal.

However running the program returns the following error (echoed from
shell, doesn't interrupt prog):
-
Exception in thread "main" java.lang.NoClassDefFoundError:
SemanticVectorsEvaluator
-

I have no idea why this isn't working. Anyone have any suggestions as
to how I might troubleshoot this?

I'd say you got an CLASSPATH-issue here. You can add that explicitly via
env as argument to Popen, or pass it via commandline-args.

Diez

 

[Edward Grefenstette]

Bingo. I was running the python script in GNU script, and it wasn't
loading my bash config file properly. Have fixed it by
altering .screenrc and now the code runs fine. Would have never
guessed to look if you hadn't mentioned it, cheers!

Best,
Ed