Question

I have a class which implements comparable to compare and sort an array of its instances on the basis of one of the class variables. Now I want to be able to search the array of this class objects using Arrays.binarySearch. For that, will overiding the equals method be enough?

Answer 1

No, binarySearch works on “more or less” comparisons rather than equality comparisons. If you’re implementing Comparable properly, such that it obeys the interface consistently, in particular returning 0 when items are equal, that should be all that’s required. (Alternatively, you can specify a Comparator.)

Of course, the array has to be ordered appropriately before binarySearch will work…