Why all elements of my list seems to be the same?

Question

I have the following code:

Integer[] lastExchange = new Integer[nColors];
Integer[] newExchange = new Integer[nColors];
while (true) {
    ...
    for (int i=0;          


        

Answer 1

As unwind's answer states, you're adding a reference to the same array in every iteration of the loop. You need to create a new array each time:

// It's not clear where newExchange is actually populated
Integer[] newExchange = new Integer[nColors];
while (true) {
    Integer[] lastExchange = new Integer[nColors];
    ...
    for (int i=0; i

Alternatively, if you're just cloning the array:

Integer[] newExchange = new Integer[nColors];
while (true) {
    Integer[] lastExchange = newExchange.clone();
    ...
    exchanges.add(lastExchange);
    output.log.fine("Exchange:" + lastExchange[0] + "," + lastExchange[1]);
}