Sorting data with Java Collections: introduction

On this and the following pages, we will look at how to sort data in Java. To start off with, we'll assume that the problem we have is the following:

By "one-off", we mean that we don't need to keep the list permanently in order as we add and remove elements, though Java does also provide 'permanently sorted' structures if that is what we require. But generally, sorting a list or array can be broken down into two problems:

Strictly speaking, these problems aren't totally separate, because some algorithms rely on us being able to measure how far apart two items are. But for sorting in Java, we can generally see the problem in the above two stages. And in fact, for most practical purposes:

In other words, for the simplest case of sorting a list of Strings or Integers (among other 'simple' objects), Java provides a one-line solution.

Where to go next...

On the next pages, we look at:


1. Actually, most of what we discuss will apply to sorting an array of primitives too.