myeclipse导出war包时报错java.lang.NullPointerException

myeclipse导出war包时，在工作空间的.metadata里的log里会有如下错误：

!ENTRY org.eclipse.jface 4 2 2014-05-29 19:24:08.682

!MESSAGE Problems occurred when invoking code from plug-in: "org.eclipse.jface".
!STACK 0
java.lang.NullPointerException
at java.lang.String.compareTo(String.java:1139)
at com.genuitec.eclipse.runtime.internal.RuntimeType.getLatestJavaVersion(RuntimeType.java:415)
at com.genuitec.eclipse.runtime.internal.RuntimeType.getRuntimeComponents(RuntimeType.java:304)
at com.genuitec.eclipse.runtime.internal.Runtime.getComponents(Runtime.java:47)
at com.genuitec.eclipse.runtime.internal.RuntimeBridge$RuntimeStub.getRuntimeComponents(RuntimeBridge.java:49)

at org.eclipse.wst.common.project.facet.core.runtime.internal.BridgedRuntime.getRuntimeComponents(BridgedRuntime.java:61)

解决办法：

myeclipse的配置问题，myeclipse引入jdk1.7就会出现这个问题，将

windows-java-installed jres里把jdk1.7删掉即可。