How I solved java.lang.UnsupportedClassVersionError

I was trying out HSQLDB to run SQL scripts with ANT last night when I encountered java.lang.UnsupportedClassVersionError. Never encountered this in 3 years of coding. Recently, I tried to play safe and installed several JDK (and JRE) versions, and so it happened.

Quick diagnostics:

  1. Run java -version from commandline, you should be able to see the JRE that is in your %PATH% environment variable
  2. Run echo %JAVA_HOME%, this is what ANT would use if you try to run ant -diagnostics from the commandline, an entry like java.home : C:\Program Files\Java\jdk1.5.0_18\jre should be there so make sure JAVA_HOME also points to an updated JRE
Published 08-25-2009 7:29 PM by lamia
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