Cant access to java.util.HashMap$Entry with modifiers "public final"

Question

My problem is, that my app works fine run locally on Tomcat server, but throws errors on server with installed glassfish. Whole problem is that i'm iterate looking through HashMap in JSTL. Server throws an stack as below:

Servlet.service() for servlet jsp threw exception java.lang.IllegalAccessException:
Class javax.el.BeanELResolver can not access a member of class java.util.HashMap$Entry with modifiers "public final" 
at sun.reflect.Reflection.ensureMemberAccess(Reflection.java:95) 
at java.lang.reflect.AccessibleObject.slowCheckMemberAccess(AccessibleObject.java:261) 
at java.lang.reflect.AccessibleObject.checkAccess(AccessibleObject.java:253)

problem is caused by code:

<c:forEach items="${element.getPreparedParameters()}" var="parametr" varStatus="j">
    documents["${i.index}"]["param"]=new Array();
    documents["${i.index}"]["param"]["key"] = "${parametr.getKey()}";
    documents["${i.index}"]["param"]["value"] = "${parametr.getValue()}";
</c:forEach>

Where element.getPreparedParameters() returns HashMap.

How can i make it work?

score 21 · Accepted Answer · edited Dec 21 '20 at 06:54

21

Check out this decades-old bug reported to Sun against Java 1.2 (fixed in Java 11). I remember seeing this error before and the message is misleading: the problem lies not with the method modifiers, but with the modifiers on the owning class. Namely, Map.Entry is a public interface, but the implementing class in HashMap is private. Reflection doesn't allow you to access the methods of the class even though you are accessing methods that implement a public interface.

I'd suggest going for a cheap workaround: don't iterate over the entrySet, but over the keySet and use map.get(key) instead of entry.getValue().

Alternative would be updating to Java 11 or newer.

edited Dec 21 '20 at 06:54

izogfif

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answered Aug 20 '12 at 13:06

Marko Topolnik

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im done with work for today, but i'll try it tommorrow morning. But question is, why does it work on Tomcat servers? – T.G Aug 20 '12 at 13:20
1

Problem solved. Iterate over keySet fixed the problem. Thanks. – T.G Aug 21 '12 at 06:59
This is very inefficient as the full map lookup happens again during every get(x). – Charles Follet Oct 04 '16 at 13:13
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@CharlesFollet "Very inefficient"---by what standard? Can you quantify the percentage it will add to the response time? – Marko Topolnik Oct 04 '16 at 13:21
As you should know, O(n) in the worst case. I will do a workbench for response time soon. – Charles Follet Oct 04 '16 at 13:45
@CharlesFollet As you should know, O(1) is the typical case, which is the point of a hashtable. – Marko Topolnik Oct 04 '16 at 13:46
@MarkoTopolnik Should have quoted [Bauke Scholtz](http://stackoverflow.com/a/10934104/3042945) – Charles Follet Oct 04 '16 at 13:47
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@CharlesFollet I don't see the point. Are you pulling an argument from authority? His advice quite obviously doesn't work, which is why this question arose in the first place. – Marko Topolnik Oct 04 '16 at 13:49
@MarkoTopolnik My knowlege ends here. My comment was just a warning I learnt from BalusC comment (that I can't share with a link). You can respond his comment if you want further informations, I would be happy to see his arguments. – Charles Follet Oct 04 '16 at 13:55
@CharlesFollet I think I already have all the information I need, but thanks. – Marko Topolnik Oct 04 '16 at 13:56

Cant access to java.util.HashMap$Entry with modifiers "public final"

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