A. Sundararajan's Weblog

"helloworld" with Maxine JVM on Mac

Last night, I listened to this nice podcast on Maxine JVM from Software Engineering Radio. Maxine is a Java Virtual Machine implemented in the Java programming language.

I wanted to try out Maxine on my MacBook Pro running Mac OS X 10.5.8. I followed these steps to try it out:

• Get the Maxine sources

  
      hg clone https://kenai.com/hg/maxine~maxine maxine
  
  

• Setup the environment

  
      export JAVA_HOME=/System/Library/Frameworks/JavaVM.framework/Versions/1.6.0/Home
      export JUNIT4_CP=<full-path-of junit-4.4.jar>
  
  

• Build Maxine

  
     cd $MAXINE_HOME/bin
     ./max build
     ./max image   
  
  

• Run the "helloworld"

  
      ./max helloworld
  
  

Wow! Maxine VM printed "Hello World!". Now, it is time to explore Maxine's inspector and other cool stuff ...

( Sep 17 2009, 10:24:54 AM IST ) Permalink | | | | |

java.lang.NoClassDefFoundError: com/sun/javafx/runtime/FXBase

I created a simple JavaFX applet and compiled it with "javafxc" and created a jar "HelloApplet.jar". Then, I created a simple HTML file as follows:

<script src="http://dl.javafx.com/dtfx.js"></script>
<script>
           javafx(
           {
               archive: "HelloApplet.jar",
               draggable: true,
               width: 150,
               height: 100,
               code: "hello.HelloApplet",
               name: "HelloApplet"
           }
       );
</script>

When viewing the HTML, I did not see the expected applet content in it - just a gray rectangle panel Then, I turned on the "Show Java Console" option. I saw the following exception trace in Java console:

JNLPAppletLauncher: static initializer
Exception in thread "AWT-EventQueue-2" java.lang.NoClassDefFoundError: com/sun/javafx/runtime/FXBase
	at java.lang.ClassLoader.defineClass1(Native Method)
	at java.lang.ClassLoader.defineClass(ClassLoader.java:675)
	at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:124)
	at java.net.URLClassLoader.defineClass(URLClassLoader.java:260)
	at java.net.URLClassLoader.access$100(URLClassLoader.java:56)
	at java.net.URLClassLoader$1.run(URLClassLoader.java:195)
[.. more stack frames deleted for brevity ..]

Aha! com.sun.javafx.runtime.FXBase is new since JavaFX 1.2. Yes, I had compiled my applet with JavaFX 1.2 (full version "1.2.0_b233"). So, the JavaFX runtime used turned out to be old one! I changed the HTML script URL from http://dl.javafx.com/dtfx.js to http://dl.javafx.com/1.2/dtfx.js. The applet worked as expected

( Sep 02 2009, 08:05:47 PM IST ) Permalink | | | | |