Question

I have the following code:

Map<String, ObjectType> objectMap = new HashMap<String, ObjectType>();
for (ObjectType obj : objects) {
    obj.setSomeProperty("property value");
    objectMap.put(obj.getADiffProperty(), obj);
}

It seems like during loop iteration some of the obj property changes for different keys than the one currently being set. Is there a problem with the above code? Somehow the reference to obj is being recycled by the for loop?

Also this loop is in an outer loop as well.

Update:
I am providing the full method below. The actual place where I am observing the behavior described above is in the outer map defined as Map<String, Map<String, GlossaryTerm>> loadedTerms = new HashMap<String, Map<String, GlossaryTerm>>(); defined in a Singleton class.

List<Audience> audiences = ContentAccess.getAudienceList();

List<GlossaryTerm> glossaryTerms = ContentAccess.getAllReplacementCIs();                            

for (Audience audience : audiences) {                   
    Map<String, GlossaryTerm> termMap = new HashMap<String, GlossaryTerm>();
    for (GlossaryTerm term : glossaryTerms) {
       String definition = term.getProductGlossary().get(audience.getName());
       if (definition != null)
           term.setDefinition(definition);
       termMap.put(term.getPhrase(), term);
   }                        
   loadedTerms.put(audience.getChannelId(), termMap);
}

Answer 1

I’m starting a new answer because – well, it’s a new thought here, and the discussion thread was getting rather long.

You haven’t (I think) said when the changes happen. But you are (potentially) putting the same term into multiple maps, for different audiences. Nothing to do with the loop variable – just that you are repeatedly using the same list of terms, for each audience. But when you put the term into a map, you also change its definition. But the definition is (potentially) different for each audience. So, concrete example:

Term A has the definition of “x” for audience X, and “y” for audience Y. You have both audiences. Initially, we encounter audience X, so A gets definition “x”. A gets added to the map for this audience. Now we iterate to the next audience, and change the definition for A to “y”. This changes A everywhere you have a reference to it – including in the map for audience X. This would explain why making a copy eliminates the problem. Is this what you are experiencing?