JavaScript performance degraded after moving to Java 8

Issue

• We moved to java 8 and see notably slower performance. Thread dumps show large amounts of processing time in nashorn, for example:

   java.lang.Thread.State: RUNNABLE
    at java.lang.Class.getDeclaredFields0(Native Method)
    at java.lang.Class.privateGetDeclaredFields(Class.java:2583)
    at java.lang.Class.getDeclaredField(Class.java:2068)
    at jdk.nashorn.internal.runtime.Context$ContextCodeInstaller$1.run(Context.java:213)
    at jdk.nashorn.internal.runtime.Context$ContextCodeInstaller$1.run(Context.java:208)
    at java.security.AccessController.doPrivileged(Native Method)
    at jdk.nashorn.internal.runtime.Context$ContextCodeInstaller.initialize(Context.java:208)
    at jdk.nashorn.internal.codegen.CompilationPhase$14.transform(CompilationPhase.java:568)
    at jdk.nashorn.internal.codegen.CompilationPhase.apply(CompilationPhase.java:716)
    at jdk.nashorn.internal.codegen.Compiler.compile(Compiler.java:620)
    at jdk.nashorn.internal.runtime.Context.compile(Context.java:1316)
    - locked <0x00000007511175c0> (a jdk.nashorn.internal.runtime.Context)
    at jdk.nashorn.internal.runtime.Context.compileScript(Context.java:1248)
    at jdk.nashorn.internal.runtime.Context.compileScript(Context.java:629)
    at jdk.nashorn.api.scripting.NashornScriptEngine.compileImpl(NashornScriptEngine.java:532)
    at jdk.nashorn.api.scripting.NashornScriptEngine.compileImpl(NashornScriptEngine.java:521)
    at jdk.nashorn.api.scripting.NashornScriptEngine.evalImpl(NashornScriptEngine.java:399)
    at jdk.nashorn.api.scripting.NashornScriptEngine.eval(NashornScriptEngine.java:155)
    at javax.script.AbstractScriptEngine.eval(AbstractScriptEngine.java:264)