My humble greetings, monks,

I am trying to automate a command-line Java application (Project X to be exact), and am trying to use the secure form of system() or pipe from it. However, when I do that, I am merely greeted with an error from Java:

Failed to load Main-Class manifest attribute from ~/src/Project-X_0.91.0/ProjectX.jar

Here's what I am trying:

# works
system("java -jar ~/src/Project-X_0.91.0/ProjectX.jar -demux");

# doesn't work
system(qw#java -jar ~/src/Project-X_0.91.0/ProjectX.jar -demux#);

# doesn't work
open($fh, '-|', qw#java -jar ~/src/Project-X_0.91.0/ProjectX.jar -demu
+x#);

print while (<$fh>);

close $fh;
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What could be the cause of difference in execution? The Java I'm using is GCJ version 4.4.5, for what it is worth.