title: Java Can't connect to X11 window server using 'localhost:10.0' as the value of the DISPLAY variable
body: <p>I have a script using java to connect to display X11 in the port 10.0 at localhost</p>
  
  <p>but i get always this error</p>
  
  <pre><code>java.lang.InternalError: Can't connect to X11 window server using 'localhost:10.0' as the value of the DISPLAY variable.
      at sun.awt.X11GraphicsEnvironment.initDisplay(Native Method)
      at sun.awt.X11GraphicsEnvironment.access$200(X11GraphicsEnvironment.java:62)
      at sun.awt.X11GraphicsEnvironment$1.run(X11GraphicsEnvironment.java:178)
      at java.security.AccessController.doPrivileged(Native Method)
      at sun.awt.X11GraphicsEnvironment.&lt;clinit&gt;(X11GraphicsEnvironment.java:142)
      at java.lang.Class.forName0(Native Method)
      at java.lang.Class.forName(Class.java:186)
      at java.awt.GraphicsEnvironment.getLocalGraphicsEnvironment(GraphicsEnvironment.java:82)
      at sun.awt.X11.XToolkit.&lt;clinit&gt;(XToolkit.java:112)
      at java.lang.Class.forName0(Native Method)
      at java.lang.Class.forName(Class.java:186)
      at java.awt.Toolkit$2.run(Toolkit.java:849)
      at java.security.AccessController.doPrivileged(Native Method)
      at java.awt.Toolkit.getDefaultToolkit(Toolkit.java:841)
      at ij.io.Opener.openJpegOrGif(Opener.java:367)
      at ij.io.Opener.openImage(Opener.java:220)
      at ij.io.Opener.openImage(Opener.java:249)
      at ij.io.Opener.open(Opener.java:116)
      at ij.IJ.open(IJ.java:1112)
      at ij.macro.Functions.open(Functions.java:2006)
      at ij.macro.Functions.doFunction(Functions.java:129)
      at ij.macro.Interpreter.doStatement(Interpreter.java:205)
      at ij.macro.Interpreter.doBlock(Interpreter.java:515)
      at ij.macro.Interpreter.runUserFunction(Interpreter.java:278)
      at ij.macro.Interpreter.getFactor(Interpreter.java:1200)
      at ij.macro.Interpreter.getTerm(Interpreter.java:1162)
      at ij.macro.Interpreter.getExpression(Interpreter.java:1145)
      at ij.macro.Interpreter.getBooleanExpression(Interpreter.java:881)
      at ij.macro.Interpreter.getLogicalExpression(Interpreter.java:857)
      at ij.macro.Interpreter.getBoolean(Interpreter.java:850)
      at ij.macro.Interpreter.doIf(Interpreter.java:829)
      at ij.macro.Interpreter.doStatement(Interpreter.java:217)
      at ij.macro.Interpreter.doBlock(Interpreter.java:515)
      at ij.macro.Interpreter.doStatement(Interpreter.java:241)
      at ij.macro.Interpreter.doIf(Interpreter.java:831)
      at ij.macro.Interpreter.doStatement(Interpreter.java:217)
      at ij.macro.Interpreter.doStatements(Interpreter.java:195)
      at ij.macro.Interpreter.run(Interpreter.java:99)
      at ij.macro.Interpreter.run(Interpreter.java:65)
      at ij.macro.Interpreter.run(Interpreter.java:75)
      at ij.plugin.Macro_Runner.runMacro(Macro_Runner.java:127)
      at ij.plugin.Macro_Runner.runMacroFile(Macro_Runner.java:112)
      at ij.IJ.runMacroFile(IJ.java:103)
      at ij.ImageJ.main(ImageJ.java:517)
  </code></pre>
  
  <p>I have tried everything to solve this problem like :</p>
  
  <pre><code>export DISPLAY=:10.0
  export DISPLAY=localhost:10.0
  </code></pre>
  
  <p>I tried also the port 0.0 but i get always the same error</p>
  
  <p>after trying xhost </p>
  
  <pre><code>xhost +local:all
  xhost:  unable to open display ""
  xhost:  unable to open display ":10.0"
  </code></pre>
  
  <p>how can i fix this
  i thought that the X Server is not runing so i tried <code>startx</code> its says its runing at that port </p>
  
  <p>my system is Ubuntu server edition 10.04</p>