How to get the assigned variable back out of an Array?

I created an array of objects:

Object[] r = new Object[2];

I assigned a variable of a class to r:

r[0] = Start;

Start is of type SDTNode which is a class I created.

Now I want to get the value back:

SDTNode end = r[0];

It is giving me an erro开发者_高级运维r. Is there a way to do this?

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If you know that all elements of r are SDTNode objects, then you should have defined it like this:

SDTNode[] r = new SDTNode[2];

Otherwise, the type information about the content will be "some Object, we don't know the specifics" and you'll have to cast:

SDTNode end = (SDTNode) r[0];

This will always compile, but will fail at runtime if r[0] does not in fact reference a SDTNode.

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You need to cast it:

SDTNode end = (SDTNode)r[0];