Unable to compile java extension from Integration studio.

  
When pressing in integration studio
- Verify: OK,
- Updating source code: OK,
- Compiling: NOK  (new batch.xml created and in placed in correct folder).

My configuration settings were:
-J2EE Integrated Development environment: C:\apps\eclipse\eclipse.exe
-Compiler complience level set to 1.6
-Compiler tool: C:\apps\eclipse\apache-ant-1.8.4\bin\ant.bat

As suggested by ANT-user forum: changing
        <javac srcdir="${src}" destdir="${build}"> <classpath refid="classpath" /> </javac>  into:
        <javac srcdir="${src}" destdir="${build}" includeantruntime="false"> <classpath refid="classpath" /></javac>  did not help.
Please could anyone provide me with a useful suggestion to get this working properly?

Error-message + stack trace:

J2EE Compilation. Buildfile: C:\extensions\Test\Source\J2EE\build.xml init: compile: BUILD FAILED
C:\extensions\Test\Source\J2EE\build.xml:34: java.lang.UnsupportedClassVersionError: com/sun/tools/javac/Main (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 java.lang.ClassLoader.loadClass(Unknown Source)
    at java.lang.ClassLoader.loadClassInternal(Unknown Source)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Unknown Source)
    at org.apache.tools.ant.taskdefs.compilers.CompilerAdapterFactory.doesModernCompilerExist(CompilerAdapterFactory.java:166)
    at org.apache.tools.ant.taskdefs.compilers.CompilerAdapterFactory.getCompiler(CompilerAdapterFactory.java:125)
    at org.apache.tools.ant.taskdefs.Javac.findSupportedFileExtensions(Javac.java:979)
    at org.apache.tools.ant.taskdefs.Javac.scanDir(Javac.java:956)
    at org.apache.tools.ant.taskdefs.Javac.execute(Javac.java:927)
    at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:291)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)
    at org.apache.tools.ant.Task.perform(Task.java:348)
    at org.apache.tools.ant.Target.execute(Target.java:392)
    at org.apache.tools.ant.Target.performTasks(Target.java:413)
    at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1399)
    at org.apache.tools.ant.Project.executeTarget(Project.java:1368)
    at org.apache.tools.ant.helper.DefaultExecutor.executeTargets(DefaultExecutor.java:41)
    at org.apache.tools.ant.Project.executeTargets(Project.java:1251)
    at org.apache.tools.ant.Main.runBuild(Main.java:811)
    at org.apache.tools.ant.Main.startAnt(Main.java:217)
    at org.apache.tools.ant.launch.Launcher.run(Launcher.java:280)
    at org.apache.tools.ant.launch.Launcher.main(Launcher.java:109)
Hello Bas,

take a look in this topic http://www.outsystems.com/forums/discussion/9519/how-to-configure-integration-studio-to-work-with-net-and-java-j2ee-extensions/

The Guides & How-tos section has lots of tips for beginners and advanced users of Outsystems.
Thanks Joao, indeed it all came down to correct system environment variables. It's working fine now!