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Change the object instance type

mesagir sajib

Joined: Sep 26, 2012
Posts: 1
[Added code tags - see UseCodeTags]

can anyone clarify this topic.
Matthew Brown

Joined: Apr 06, 2010
Posts: 4541

Hi Mesagir. Welcome to the Ranch!

What exactly is your question? Is it about what's happening on line 11? That's a cast. It doesn't actually change the type of the object, but it changes the type of the reference. Without that cast, you couldn't assign the results to a MyClass variable - the compiler would prevent it. Using the cast is telling the compiler "I know that elementAt says it's returning an Object, but I know it's really returning a MyClass, so treat it like that". The JVM then throws an exception at runtime if that isn't actually true.

Using generic collections (e.g an ArrayList<MyClass>) avoids this.
I agree. Here's the link:
subject: Change the object instance type
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