should be using JavaSE-1.6 VM, and .classpath, codegen.targetPlatform, compliance and source should also all be 1.6;
making these changes requires the project to have custom compiler settings in order to continue to import XPathAPI
from its original location com.sun.org.apache.xpath.internal, which is still in JavaSE-1.6 rt.jar .
<?xml version="1.0" encoding="UTF-8"?>
<classpath>
<classpathentry kind="src" path="src"/>
<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/J2SE-1.5"/>
<classpathentry kind="con" path="org.eclipse.pde.core.requiredPlugins"/>
<classpathentry kind="output" path="bin"/>
</classpath>