MessageHeaders mutable through Map.Entry.setValue() [SPR-13385]

[spring-projects-issues]

Andrei Amariei opened SPR-13385 and commented

org.springframework.messaging.MessageHeaders can be modified using Map.Entry.setValue() method like in the following snippet:

Integer value = 123;
Map<String, Object> map = new HashMap<String, Object>();
map.put("test", value);
MessageHeaders headers = new MessageHeaders(map);
headers.entrySet().iterator().next().setValue(124);

Immutability should be achievable using something like in java.util.Collections.UnmodifiableMap.entrySet()

Doesn't seem like a big problem, but it's in contradiction with the documentation of the class which describes it as immutable

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Affects: 4.2 GA

Issue Links:

• MessageHeaders is declared immutable - but writeObject() removes any non-serializable fields [SPR-13541] #18117 MessageHeaders is declared immutable - but writeObject() removes any non-serializable fields

Referenced from: commits 8cd2837

[spring-projects-issues]

Rossen Stoyanchev commented

MessageHeaders overrides entrySet and returns UnmodifiableMap.entrySet(this.headers.entrySet()). What's missing?

[spring-projects-issues]

Andrei Amariei commented

Hope I'm not looking in the wrong place.
MessageHeaders on master branch seems to override entryset() so that it returns Collections.unmodifiableSet(this.headers.entrySet()).

What's the UnmodifiableMap class you're mentioning? The one from Collections class shouldn't be accessible as it's private.

[spring-projects-issues]

Juergen Hoeller commented

Indeed, we should be using Collections.unmodifiableMap(this.headers).entrySet() there. Good catch!

Juergen