title: How to solve "Symbol lookup error" by using JPL on Ubuntu11.04?
body: <p>I'm coding a program in Java and I would like to connect to Prolog. Thus, I decided to use JPL. It is perfectly to use JPL on Windows Vista. Later, I have to change the OS platform to be Ubuntu 11.04. Unfortunately, there is an error:</p>
  
  <blockquote>
    <p>symbol lookup error: /usr/lib/swi-prolog/lib/i386/libjpl.so: undefined symbol: PL_is_initialised</p>
  </blockquote>
  
  <p><strong>Environment:</strong></p>
  
  <ol>
  <li>Ubuntu 11.04</li>
  <li>Java version 1.6.0_24</li>
  <li>Eclipse Galileo  Version: 3.5.2</li>
  <li>SWI-Prolog version 5.10.1 for i386</li>
  <li>Jpl (apt-get install swi-prolog-java)</li>
  <li>Family.java + family.pl</li>
  </ol>
  
  <p>I explain steps of working and problems as follows.
   step1: Install swi-prolog + jpl using Synaptic Package Manager 
  <img src="https://i.stack.imgur.com/nTxml.jpg" alt="Swi-prolog Installation"></p>
  
  <p>step2: Run Family.java , found an <strong>error</strong> 
  <img src="https://i.stack.imgur.com/rrDPD.png" alt="JPL not found Error"></p>
  
  <p>step3: Configure the library path at <strong>VMarguments</strong> 
  <img src="https://i.stack.imgur.com/ciFXF.png" alt="Set VMarguments">
  step4: Run again, there is an error 
  <strong>/usr/lib/jvm/java-6-sun-1.6.0.24/bin/java: symbol lookup error: /usr/lib/swi-prolog/lib/i386/libjpl.so: undefined symbol: PL_is_initialised</strong>
  step5: I also config the environment but the error still the same. 
  <img src="https://i.stack.imgur.com/mKKVq.png" alt="set environment arguments"></p>
  
  <p>The method that I used to solve the problem as in step 3 and 5 I searched from the internet. I can not find other solutions to try. Does anyone have any idea?<br>
  Thanks in advance.  </p>