The

java.lang.AbstractMethodError

is thrown because a Class that is required to run it hasn't run or didn't get any info. So you should look at the classes that this Abstract method/class uses.

Hmmm... Okay, I can't figure that one out. Sorry T_T

Try

while(Card c: col)
    {
        return c;
    }

or

for(int i = 0; i < col.length(); i++)
{
return c;
}

**These may work or may not, I only started learning java for 2-3 months now. Forgive me if these don't work :3

This might be useful for you, read the answer -> Click Here

I've found a usefull explanation of a 2D array for you. Click Here Look at the answer.

For you to implement in the code above, I think that you need to make the "int random = 0" to a multi dimensional. Like 'int[][] random = new int[X][]' X = Rows, 5 rows = 0-4. Etc and to assign the amount of fields it has you do: "random[0] = new int[5]" This gives row 0 (basicly 1) 5 fields

Yes, like i said, JTextField, JButton(Along with a ActionListener) and methods(Inserting 'fieldinput.getText(fieldinput)' ) to do the insertion.

Have a look at this post, maybe it will help you :) Click Here

You should first create the textfield by declaring them obviously. ( JTextField fieldinput, fieldoutput; ) No idea how many fields you want.

Also what -stultuske' mentioned, you can use the setText method like: fieldinput.getText(fieldinput) and fieldoutput.setText(fieldinput).

You need buttons to make them operate. You have to use the ActionListener for that.

I hope this helps.

Can you please repost this, and place an "description" above each file source what it is used for? I would love to help you, but atleast show some effort.