Passing an ArrayList of any type to a method
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I'm working on my first Android app, a math game for my kid, and am learning Java in the process.  I have two ArrayLists, one of integers 0..9 and one strings of possible operations, at present, just '+' and '-'.

I would like to write a method that returns a random index into an ArrayList, so I can select a random element.  What I'm running into is that I need two methods, one for each type of ArrayList, even though the code is identical.  Is there a way to do this in a single method?

What I use now:

    Random randomGenerator = new Random();

      . . .

    n = randomIndexInt(possibleOperands);
    int op1 = possibleOperands.get(n);
    n = randomIndexInt(possibleOperands);
    int op2 = possibleOperands.get(n);
    n = randomIndexStr(possibleOperations);
    String operation = possibleOperations.get(n);

        . . .

    int randomIndexInt(ArrayList<Integer> a){
    	int n = randomGenerator.nextInt(a.size());
    	return n;
    }
    
    int randomIndexStr(ArrayList<String> a){
    	int n = randomGenerator.nextInt(a.size());
    	return n;
    }

What I'd like to do is collapse randomIndexInt and randomIndexStr into a single method.