Java lists
 Sorting data in Java
 Sorting strings in Java
 Java maps
 Hash codes: introduction
 Hash function guidelines
 Advanced use of hash codes
 Video: Hash tables

Collections in Java

A collection is a general term that means something like "a bunch of objects stored in a structured manner". Java has various standard collection classes and using collections in Java allows you to organise data in memory in various convenient ways. Examples might include:

The Java Collections Framework— often called simply (Java) Collections— is a library of classes that implement these and various other data structures. The collections framework also provides utility methods to perform functions such as sorting a list of data.

How to start learning about and using Java collections

There are a couple of ways to approach collections in Java, covered by the collections tutorials in the rest of this section:

Advanced use of hashing techniques

More advanced readers may wish to take a look at the section on advanced use of hash codes. In this section, we see how to exploit some statistical properties of hash codes to reduce the amount of memory needed to perform certain tasks, notably duplicate elimination.