compile with ant

[upul]

Hi all;
I am new to the ant and I used following java example and it worked,
when I used it with ant.
package oata;
public class HelloWorld{
public static void main(String[] args){
System.out.println("Hello Ant");
}
}

Build file is
<project>

<target name="clean">
<delete dir="build"/>
</target>

<target name="compile">
<mkdir dir="build/classes"/>
<javac srcdir="src" destdir="build/classes"/>
</target>

<target name="jar">
<mkdir dir="build/jar"/>
<jar destfile="build/jar/HelloWorld.jar" basedir="build/classes">
<manifest>
<attribute name="Main-Class" value="oata.HelloWorld"/>
</manifest>
</jar>
</target>

<target name="run">
<java jar="build/jar/HelloWorld.jar" fork="true"/>
</target>

</project>

(source: http://ant.apache.org/manual/tutorial-HelloWorldWithAnt.html)
I am using jdk1.5.0 and apache ant 1.6.2


But when it runs in the command prompt using following command, it gave
me following error messages.

E:\build\jar>java -jar HelloWorld.jar
Exception in thread "main" java.lang.UnsupportedClassVersionError:
oata/HelloWor
ld (Unsupported major.minor version 49.0)
at java.lang.ClassLoader.defineClass0(Native Method)
at java.lang.ClassLoader.defineClass(Unknown Source)
at java.security.SecureClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.access$100(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClassInternal(Unknown Source)

Please help me to solve this problem
Thanks

 

[Roedy Green]

java.lang.UnsupportedClassVersionError

Try upgrading or reverting your JVM. This is likely a bug — some
native method not prepared to function under the current version. Try
uninstalling all your java, purging the files, then reinstall your
JDKs and JREs, working from oldest to newest. The problem is caused by
some sort of clash with code from one version interacting with code
from another.