All elements of An ArrayList change when a new one is added? [duplicate]

Answer 1

ArrayList just stores reference of elements. Ensure that your code looks like:

ArrayList list = new ArrayList<>();
loop(...) {
    MyObject newOne = new MyObject();
    newOne.setXXX(xxx);
    list.add(newOne);
}

Wrong code:

ArrayList list = new ArrayList<>();
MyObject sameOne = new MyObject();
loop(...) {
    sameOne.setXXX(xxx);
    list.add(sameOne);
}

Answer 2

I've seen folks report this kind of problem many times, and it always comes down to this: you're actually not creating a new instance, but instead using the same one for each iteration of the loop. It's an easy mistake to make, especially if you're coming from a language with different copy semantics. There are a number of different ways you can make this mistake; if you edit your question to show the loop code, I'm sure I'll be able to explain what's happening.

OK, now that you've added the code: the problem is that in "Content", all the data member are marked "static". In Java, that means that there's one variable shared by all objects -- i.e., the variable has the same value for every object. SO in fact you are creating many Content objects to put in the ArrayList, but they all look identical! Remove those "static" attributes from Content's data members, and you'll be all set.