title: Update jython.jar in PyDev
body: <p>What is the proper way to apply a new jython.jar to PyDev?</p>
  
  <p>I expect this option to be available since I have to supply a Jython interpreter at startup. Using mixed versions would likely cause issues. I expected the jython.jar for that interpreter to be used for everything, not just running standalone Jython, but that doesn't appear to be the case.</p>
  
  <p>I believe org.python.pydev.jython provides a version of jython.jar. The version of this plugin in PyDev 2.7.1 has a pydev-jython.jar that is on the runtime classpath when I import this plugin. (The import also makes a copy of the directory of my configured Jython interpreter.)</p>
  
  <p>How do I get PyDev to use a different jython.jar?</p>
  
  <p>Here is some more background information.</p>
  
  <p>I have followed the instructions on the PyDev website for installing PyDev in Eclipse. I have configured Jython 2.5.3 to be the interpreter.</p>
  
  <p>I can open a Jython console and run the following:</p>
  
  <pre><code>&gt;&gt;&gt; import org.python.core.PySystemState as pss
  &gt;&gt;&gt; st = pss()
  &gt;&gt;&gt; st.getBuiltins
  &lt;bound method &lt;reflected field public org.python.core.PyObject org.python.core.PySystemState.__name__ at 0x1&gt;.getBuiltins of &lt;module 'sys' (built-in)&gt;&gt;
  </code></pre>
  
  <p>I also have no problem doing this from a python module that I run as a Jython Run.</p>
  
  <p>However, when I try to access getBuiltins from java, I get a compile-time error stating that the method getBuiltins is not defined for PySystemState. As I have fought with this problem extensively, I believe what is going on is that org.python.pydev.jython is providing jython.jar whereas the interpreter configuration is only used to run the Jython interpreter.</p>
  
  <p>Clearly, some jython.jar is in my classpath because I don't get a complaint when I import org.python.core.PySystemState. The symptoms are consistent with an older jython.jar that didn't have the full API of Jython 2.5.3.</p>
  
  <p>Any help would be appreciated -- I'd prefer not to earn another tumbleweed bronze! :-)</p>