Steps to reproduce:
- Start jhat with any hprof file
- Open OQL query page
- Enter query: "heap.forEachClass(function() { })"

Output:
java.lang.reflect.InvocationTargetException com.sun.tools.hat.internal.oql.OQLException: java.lang.reflect.InvocationTargetException
at com.sun.tools.hat.internal.oql.OQLEngine.executeQuery(OQLEngine.java:95)
at com.sun.tools.hat.internal.server.OQLQuery.executeQuery(OQLQuery.java:88)
at com.sun.tools.hat.internal.server.OQLQuery.run(OQLQuery.java:80)
at com.sun.tools.hat.internal.server.HttpReader.run(HttpReader.java:194)
at java.lang.Thread.run(Thread.java:722)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.GeneratedMethodAccessor2.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:487)
at com.sun.tools.hat.internal.oql.OQLEngine.evalScript(OQLEngine.java:240)
at com.sun.tools.hat.internal.oql.OQLEngine.executeQuery(OQLEngine.java:92)
... 4 more
Caused by: javax.script.ScriptException: TypeError: java.util.Collections$UnmodifiableCollection$1@530d0c has no such function "hasMoreElements" in at line number 498
at jdk.nashorn.api.scripting.NashornScriptEngine.throwAsScriptException(NashornScriptEngine.java:421)
at jdk.nashorn.api.scripting.NashornScriptEngine.evalImpl(NashornScriptEngine.java:405)
at jdk.nashorn.api.scripting.NashornScriptEngine.evalImpl(NashornScriptEngine.java:384)
at jdk.nashorn.api.scripting.NashornScriptEngine.eval(NashornScriptEngine.java:135)
at javax.script.AbstractScriptEngine.eval(AbstractScriptEngine.java:264)
... 9 more
Caused by: :498 TypeError: java.util.Collections$UnmodifiableCollection$1@530d0c has no such function "hasMoreElements"
at jdk.nashorn.internal.runtime.ECMAErrors.error(ECMAErrors.java:66)
at jdk.nashorn.internal.runtime.ECMAErrors.typeError(ECMAErrors.java:222)
at jdk.nashorn.internal.runtime.ECMAErrors.typeError(ECMAErrors.java:194)
at jdk.nashorn.internal.runtime.ECMAErrors.typeError(ECMAErrors.java:181)
at jdk.nashorn.internal.runtime.linker.NashornBottomLinker.linkBean(NashornBottomLinker.java:93)
at jdk.nashorn.internal.runtime.linker.NashornBottomLinker.getGuardedInvocation(NashornBottomLinker.java:64)
at jdk.internal.dynalink.support.CompositeGuardingDynamicLinker.getGuardedInvocation(CompositeGuardingDynamicLinker.java:124)
at jdk.internal.dynalink.support.LinkerServicesImpl.getGuardedInvocation(LinkerServicesImpl.java:138)
at jdk.internal.dynalink.DynamicLinker.relink(DynamicLinker.java:229)
at jdk.nashorn.internal.scripts.Script$\^eval\_.wrapHeapSnapshot$_L493(:498)
at jdk.nashorn.internal.scripts.Script$\^eval\_.runScript(:1)
at jdk.nashorn.internal.runtime.ScriptFunctionData.invoke(ScriptFunctionData.java:510)
at jdk.nashorn.internal.runtime.ScriptFunction.invoke(ScriptFunction.java:205)
at jdk.nashorn.internal.runtime.ScriptRuntime.apply(ScriptRuntime.java:345)
at jdk.nashorn.api.scripting.NashornScriptEngine.evalImpl(NashornScriptEngine.java:402)
... 12 more


This is likely due to an error in hat.js:495
     var classes = this.snapshot.classes;

which should be
      var classes = this.classes();