Collections utilities

There are two classes with static methods handling collections that are very popular and helpful:

• java.util.Collections
• org.apache.commons.collections4.CollectionUtils

The fact that the methods are static means they do not depend on the object state, so they are also called stateless methods, or utilities methods.

java.util.Collections class

There are many methods in the Collections class that manage collections, and analyze, sort, and compare them. There are more than 70 of them, so we do not have a chance to talk about all of them. Instead, we are going to look at the ones most often used by mainstream application developers:

• static copy(List<T> dest, List<T> src): This copies elements...