How to sort an arraylist of objects java?

Question

So I want an arraylist of objects in java.

I have object1.number and object2.number, object3.number, etc... but those objects

Answer 1

Use to Collections.sort() to sort an ArrayList in Java 8:

Collections.sort(array, new Comparator() {
    @Override
    public int compare(Class o1, Class o2) {
        //compare object properties
    }
});