Jaikiran, I looked into Hibernate Validator's class org.hibernate.validator.internal.util.scriptengine.ScriptEvaluatorFactory, especially the1st line in the method createNewScriptEvaluator:
ScriptEngine engine = new ScriptEngineManager().getEngineByName( languageName );

This is plain Java code. See http://docs.oracle.com/javase/7/docs/api/javax/script/ScriptEngineManager.html#getEngineByName%28java.lang.String%29
getEngineByName is searching until it finds a script engine, and for each failing trial/test it just prints an error message. There is no chance to catch an exception or test e.g. for the existance of a new Java 8 interface like java.util.function.Function or java.util.stream.CloseableStream