title: Error when I am trying to run JAR file
body: <p>thanks for attention, I struggled with such issue:
  I packed a JAR file with external libraries in Intellij Idea but when I am trying to lounch it, I see error: </p>
  
  <pre><code> The file "city-data.json" is missing or inaccessible, make sure the URL is valid or that the file has been added to your sketch and is readable.
  Exception in thread "Animation Thread" java.lang.NullPointerException
          at processing.core.PApplet.join(PApplet.java:8950)
          at de.fhpotsdam.unfolding.data.GeoJSONReader.loadData(Unknown Source)
          at Map.setup(Map.java:45)
          at processing.core.PApplet.handleDraw(PApplet.java:2361)
          at processing.core.PGraphicsJava2D.requestDraw(PGraphicsJava2D.java:240)
          at processing.core.PApplet.run(PApplet.java:2256)
          at java.lang.Thread.run(Unknown Source)
  </code></pre>
  
  <p>But I see this file in this Jar 
  <a href="http://i.stack.imgur.com/1eWY4.png" rel="nofollow">archive !</a>
  When i lounch project from Intellij or Eclipse all works good. Please, help, what problem it can be.</p>
  
  <p>Also i will be very grateful if somebody tell, how I can to collect all project to Jar file from the command line. I tried to make it with the help of commands such as</p>
  
  <pre><code> jar cvfe MyJarName.jar MyMainClass *.class
  </code></pre>
  
  <p>but it don't work too, command line answered with a lot of errors like
  <a href="http://i.stack.imgur.com/5BC9r.png" rel="nofollow">this</a></p>