76. When to use different collection types?
Collection framework provides interfaces and class implementations that enable easy data handling, i.e. store, retrieve and manipulate the data very effectively and easily. The basic types are Lists, Set & Maps.
1. Lists: no of items written one-by-one, usually ordered. Can be accessed using index. Say you want to store a list of web elements (e.g. all the hyperlinks). Implementations - ArrayList, LinkedList, Vector.
2. Set: a collection of unique items, i.e. no duplicates. Say you don't want duplicates in a database. Implementations - HashSet, LinkedHashSet, TreeSet.
3. Maps: a collection of 'Key - Value' pairs. Say you want to save key-value pairs like,
• Username - Deepanshu
• Password - *****
• Environment - SIT URL
• Browser - Firefox
Implementations - HashMap, LinkedHashMap, TreeMap.
The specific type to use depends on Test req, Test data org, multi-threading, sync-async, performance, etc.