(Java) Efficiency in my Starter Bubble Sort

Question

I am new to Java and I have a question regarding optimization.

How fast is it if I declare before my IF statement a variable that gets the value of x.indexOf(i) + 1 instead of just putting it twice in my code below (which depicts the first call of a bubblesort, without the recurency).

Is it worth to actually make a j variable which holds that x.indexOf(i) +1 instead of just letting the function run once more?

I also believe that my first condition in the IF is a bit flawed, is it possible to let the i start at a i+1 value in a foreach?

Also the use of ArrayList is mandatory.

Thanks for the answers. (Haven't read yet the Coding Standard in Java so I guess it looks ugly)

public static void bubbleOnce(ArrayList<Integer> x) {
        for(int i : x) {
            if((x.indexOf(i) != x.size()-1) && i > x.get(x.indexOf(i) + 1)) {
             Collections.swap(x, x.indexOf(i), (x.indexOf(i) + 1));       
            }
        } 
    }

Answer 1

Using indexOf is not correct, if your ArrayList x contains more than one value of i, your sort method will behave incorrectly.

For example, this case: [5, 5, 1]

After running your program, return [5, 5, 1]

Plus, using indexOf, as mentioned by tucuxi, will slow down your program.