SGD Portlet - Failed to build using Ant - UnsupportedClassVersionError

Question

Hi,
I've downloaded the Sun Secure Global Desktop portlet source code from here: https://portlet-repository.dev.java.net/public/Download.html and I'm trying to compile it using Ant.
I have Ant 1.7.0 and I'm using JRE 1.4.2_15. For some reason, the Ant task fails. Using the -debug and -logfile options, it points to a VersionTask class error:
Adding reference: ant.PropertyHelper
Detected Java version: 1.4 in: C:\Program Files\Java\j2sdk1.4.2_15\jre
Detected OS: Windows XP
Adding reference: ant.ComponentHelper
Setting ro project property: ant.file -> C:\Documents and Settings\Administrator\My Documents\Projects\2007\Sun SGD\sgdportlet\build.xml
Adding reference: ant.projectHelper
Adding reference: ant.parsing.context
Adding reference: ant.targets
parsing buildfile C:\Documents and Settings\Administrator\My Documents\Projects\2007\Sun SGD\sgdportlet\build.xml with URI = file:/C:/Documents%20and%20Settings/Administrator/My%20Documents/Projects/2007/Bell/Sun%20SGD/sgdportlet/build.xml
Setting ro project property: ant.project.name -> SGD Portlet
Adding reference: SGD Portlet
Setting ro project property: ant.file.SGD Portlet -> C:\Documents and Settings\Administrator\My Documents\Projects\2007\Sun SGD\sgdportlet\build.xml
Project base dir set to: C:\Documents and Settings\Administrator\My Documents\Projects\2007\Sun SGD\sgdportlet
+Target:
+Target: all
+Target: init
+Target: version
+Target: compile
+Target: dist
+Target: clean
[antlib:org.apache.tools.ant] Could not load definitions from resource org/apache/tools/ant/antlib.xml. It could not be found.
Setting project property: src -> C:\Documents and Settings\Administrator\My Documents\Projects\2007\Sun SGD\sgdportlet\src
Setting project property: build.top -> C:\Documents and Settings\Administrator\My Documents\Projects\2007\Sun SGD\sgdportlet\build
Setting project property: build.webinf -> C:\Documents and Settings\Administrator\My Documents\Projects\2007\Sun SGD\sgdportlet\build\WEB-INF
Setting project property: build.classes -> C:\Documents and Settings\Administrator\My Documents\Projects\2007\Sun SGD\sgdportlet\build\WEB-INF\classes
Setting project property: dist -> C:\Documents and Settings\Administrator\My Documents\Projects\2007\Sun SGD\sgdportlet\dist
Setting project property: lib -> C:\Documents and Settings\Administrator\My Documents\Projects\2007\Sun SGD\sgdportlet\lib
Setting project property: web -> C:\Documents and Settings\Administrator\My Documents\Projects\2007\Sun SGD\sgdportlet\web
Setting project property: tools -> C:\Documents and Settings\Administrator\My Documents\Projects\2007\Sun SGD\sgdportlet\tools
Setting project property: webinf -> C:\Documents and Settings\Administrator\My Documents\Projects\2007\Sun SGD\sgdportlet\web\WEB-INF
Finding class com.tarantella.tools.ant.tasks.VersionTask
Loaded from C:\Documents and Settings\Administrator\My Documents\Projects\2007\Sun SGD\sgdportlet\lib\tarantella-tasks.jar com/tarantella/tools/ant/tasks/VersionTask.class
BUILD FAILED
C:\Documents and Settings\Administrator\My Documents\Projects\2007\Sun SGD\sgdportlet\build.xml:14: java.lang.UnsupportedClassVersionError: com/tarantella/tools/ant/tasks/VersionTask (Unsupported major.minor version 50.0)
     at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:115)
I know this portlet code was just released this week, but has anybody had any success building the portlet into a .WAR file?
Thanks in advance!
Rob.

Answer 1

I figured it out... the tarantella-tasks.jar file had class files in it that were compiled using jdk 6, and the rest of the project was compiled using jdk 1.4.2. Luckily, the source code was there so that I could recompile the classes back to 1.4.2 and it now works.