List:     List is a ordered collection of values. It contains duplicate values. Each value is retrieved using the List Index. Ex:  List<String> temp = new List<String>(); temp.add(‘Newyork’); temp.add(‘Miami’); temp.add(‘Boston’); Set:     Set is an unordered collection of values. It does not contains duplicate values. Map:     Map is a key value pair datatype. Ex: Country (Key) … Continue reading List, Set and Map in Salesforce