Found one issue in stackoverflow http://stackoverflow.com/questions/37611959/java-8-passing-a-function-through-bindings
JS function declared in the engine scope. Invoking withoutProxy works fine. But withProxy throws java.lang.ClassCastException:
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-sh-4.1$ /opt/java/jdk1.8.0_102/bin/java Foo
1.8.0_102
Exception in thread "main" java.lang.ClassCastException: Cannot cast jdk.nashorn.api.scripting.ScriptObjectMirror to java.util.function.Function
        at java.lang.invoke.MethodHandleImpl.newClassCastException(MethodHandleImpl.java:361)
        at java.lang.invoke.MethodHandleImpl.castReference(MethodHandleImpl.java:356)
        at jdk.nashorn.internal.scripts.Script$Recompilation$5$17A$\^eval\_.proxy(<eval>:1)
        at jdk.nashorn.internal.runtime.ScriptFunctionData.invoke(ScriptFunctionData.java:639)
        at jdk.nashorn.internal.runtime.ScriptFunction.invoke(ScriptFunction.java:494)
        at jdk.nashorn.internal.runtime.ScriptRuntime.apply(ScriptRuntime.java:393)
        at jdk.nashorn.api.scripting.ScriptObjectMirror.call(ScriptObjectMirror.java:117)
        at jdk.nashorn.internal.scripts.Script$Recompilation$4$20$\^eval\_.withProxy(<eval>:1)
        at jdk.nashorn.internal.runtime.ScriptFunctionData.invoke(ScriptFunctionData.java:637)
        at jdk.nashorn.internal.runtime.ScriptFunction.invoke(ScriptFunction.java:494)
        at jdk.nashorn.internal.runtime.ScriptRuntime.apply(ScriptRuntime.java:393)
        at jdk.nashorn.api.scripting.ScriptObjectMirror.callMember(ScriptObjectMirror.java:199)
        at jdk.nashorn.api.scripting.NashornScriptEngine.invokeImpl(NashornScriptEngine.java:383)
        at jdk.nashorn.api.scripting.NashornScriptEngine.invokeFunction(NashornScriptEngine.java:190)
        at Foo.main(Foo.java:22)