Opening JSON file in JRuby throws exception when evoking the Java class files generated

Question

I use jrubyc to compile Ruby into class files. One of the Ruby files contains

dat = File.open "data.json", "r"

And there's a "data.json" file alongside. This program runs well if I directly use the jruby command.

After I compiled the Ruby files and put them into a jar, the following error appears when I run java -jar:

Exception in thread "main" org.jruby.exceptions.RaiseException: (Errno::ENOENT) data.json
at org.jruby.RubyFile.initialize(org/jruby/RubyFile.java:334)
at org.jruby.RubyIO.open(org/jruby/RubyIO.java:1144)
at RUBY.(root)(file:/Users/x5lai/Documents/rqrcode.jar!/read.rb:2)
...

To make sure that I have not put data.json in the wrong place, I have copied data.json all over the jar file, but the same error occurs.

Is there anyway to do this? Is JRuby unable to open JSON files once I have compiled the code?

Answer 1

I don't think that it is going to look inside the JAR by default. I created a small test and was able to reproduce your issue. I then did touch data.json and the code no longer had an error. I'm not sure how to specify that you want to look inside the JAR for your data file.