change some attribute in java bean in session

Question

I have a java bean in a session and I did this:

QuestionnaireBeanWrapper wrapper = ( QuestionnaireBeanWrapper ) session.getAttribute( examPart );
wrapper.getQuestionnaireBeanList().get( examNumber - 1 ).setQuestionAnswer( examAnswer );

I change an attribute in the bean. My question is should I set it again in the session? or the object in the session is changed automatically?

Yes, it will changed automatically as you cnaged is [by reference][1]. [1]: http://stackoverflow.com/questions/40480/is-java-pass-by-reference — vacuum, Nov 26 '13 at 10:51

score 0 · Answer 1 · edited May 23 '17 at 10:31

0

Yes, it will changed automatically as you changed is by reference. See similar question.

edited May 23 '17 at 10:31

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answered Nov 26 '13 at 10:53

vacuum

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score 0 · Accepted Answer · answered Nov 26 '13 at 10:54

When you retrieve the bean from session you have a reference to the bean. When a change is made on the bean through the reference the changes will be reflected in session since it points to the same object.

Try the following example:

QuestionnaireBeanWrapper wrapper = 
    ( QuestionnaireBeanWrapper ) session.getAttribute( examPart );
wrapper.getQuestionnaireBeanList().get( examNumber - 1 ).setQuestionAnswer( examAnswer );

QuestionnaireBeanWrapper wrapper2 = ( QuestionnaireBeanWrapper ) session.getAttribute( examPart );
System.out.println(( wrapper.getQuestionnaireBeanList().get( examNumber - 1 ).getQuestionAnswer() ==  wrapper2.getQuestionnaireBeanList().get( examNumber - 1 ).getQuestionAnswer())? "Same":"Different");

change some attribute in java bean in session

2 Answers2