What types of collections and their differences in java?

  

What are the differences between them?

First of all it is important to understand that Collection is a term that may be ambiguous, as there are:

• collection : That would be any data structure in which objects are stored and can be iterated;
• Collection ( java.util.Collection ): That is an interface that has the subinterfaces Set , List and Queue ; and
• Collections ( java.util.Collections ): That is a class with some static methods to be used with subclasses of Collection .

While Set , List , and Queue are collections (or collection , with lowercase "c") too, Collection 's, %. The same does not happen with java.util.Collection , which although it can be considered a collection, it does not implement the Map interface.

See below:

Themaindifferencesamongtheabovementionedinterfacesare:

• java.util.Collection:Listofthings;
• List:Listofthingswithoutrepetition;
• Set:Listwithkey-value,wherethekeymustbeunique;and
• Map:Row.

Eachinterfacehasclassesthatimplementthem.AstheyaremanyIwilljustputthecomparativetableofeachofthem,whichIthinksumsupverywellthefunctionalityofeachone:

Meaning of:

• Ordered : When a collection is ordered, it means that it is possible to iterate the collection elements in a specific, non-random order.
• Sorted : When a collection is sorted, it means that the order of the collection elements is determined according to some rule, known as sorting order.

Source: SCJP Sun Certified Programmer for Java 6

  

What situations or cases should I use in each of the different collections?

The situation depends on your need, looking at the differences listed above is very clear when one should choose one or another collection.