Ant not working in Eclipse Kepler (Java Virtual Machine Launcher - A Java Exception has occured)

Question

I recently upgraded to Eclipse Kepler, and am having issues with Ant. I am getting the Java Virtual Machine Launcher - A Java Exception has occurred error no matter which target I choose in my build files.

I tried reinstalling my JDK, and I still get the error. I am running the 7u25 version of the JDK. I have my JAVA_HOME environment variable set to C:\Progra~1\Java\jdk1.7.0_25, so I don't think this is the problem. What else could be causing the problem?

EDIT: I also tested ant in the command line and it works just fine. Is this a bug in Kepler?

EDIT 2: Here is the log of the errors:

org.eclipse.core.runtime.CoreException: Could not find one or more classes: "org.apache.tools.ant.BuildLogger". Please check the Ant classpath.
at org.eclipse.ant.core.AntRunner.problemLoadingClass(AntRunner.java:467)
at org.eclipse.ant.core.AntRunner.run(AntRunner.java:380)
at org.eclipse.ant.internal.launching.launchConfigurations.AntLaunchDelegate.runInSameVM(AntLaunchDelegate.java:307)
at org.eclipse.ant.internal.launching.launchConfigurations.AntLaunchDelegate.launch(AntLaunchDelegate.java:260)
at org.eclipse.debug.internal.core.LaunchConfiguration.launch(LaunchConfiguration.java:858)
at org.eclipse.debug.internal.core.LaunchConfiguration.launch(LaunchConfiguration.java:707)
at org.eclipse.debug.internal.core.LaunchConfiguration.launch(LaunchConfiguration.java:700)
at org.eclipse.core.externaltools.internal.model.ExternalToolBuilder.launchBuild(ExternalToolBuilder.java:181)
at org.eclipse.core.externaltools.internal.model.ExternalToolBuilder.doBuildBasedOnScope(ExternalToolBuilder.java:169)
at org.eclipse.core.externaltools.internal.model.ExternalToolBuilder.build(ExternalToolBuilder.java:88)
at org.eclipse.core.internal.events.BuildManager$2.run(BuildManager.java:726)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:199)
at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:239)
at org.eclipse.core.internal.events.BuildManager$1.run(BuildManager.java:292)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:295)
at org.eclipse.core.internal.events.BuildManager.basicBuildLoop(BuildManager.java:351)
at org.eclipse.core.internal.events.BuildManager.build(BuildManager.java:374)
at org.eclipse.core.internal.resources.Workspace.buildInternal(Workspace.java:514)
at org.eclipse.core.internal.resources.Workspace.build(Workspace.java:423)
at org.eclipse.debug.internal.core.LaunchConfiguration.launch(LaunchConfiguration.java:830)
at org.eclipse.debug.internal.core.LaunchConfiguration.launch(LaunchConfiguration.java:707)
at org.eclipse.debug.internal.ui.DebugUIPlugin.buildAndLaunch(DebugUIPlugin.java:1018)
at org.eclipse.debug.internal.ui.DebugUIPlugin$8.run(DebugUIPlugin.java:1222)
at org.eclipse.core.internal.jobs.Worker.run(Worker.java:53)

Caused by: java.lang.NoClassDefFoundError: org/apache/tools/ant/BuildLogger
at java.lang.Class.getDeclaredConstructors0(Native Method)
at java.lang.Class.privateGetDeclaredConstructors(Unknown Source)
at java.lang.Class.getConstructor0(Unknown Source)
at java.lang.Class.newInstance(Unknown Source)
at org.eclipse.ant.core.AntRunner.run(AntRunner.java:324)
... 24 more

Caused by: java.lang.ClassNotFoundException: org.apache.tools.ant.BuildLogger
at java.net.URLClassLoader$1.run(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 org.eclipse.ant.internal.core.AntClassLoader.findClass(AntClassLoader.java:54)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
... 29 more

Answer 1

For me the problem were the JDK I were trying to use. The project I wanted to build was setup to use the 1.6 JDK. I got the same error as the questioner, but when I changed to Java 8 the build worked fine. So I am assuming that the ANT version that comes with newer versions Eclipse does not work with older JDKs.