Question
Difference between List< ? > and List < Object > in Java
Answers
This generics interview question may look related to previous interview questions but completely different. List< ? > is List of unknown type while List< Object > is essentially List of any Type. You can assign List , List to List< ? > but you can not assign List to List< Object >.

List< ?> listOfAnyType;
List< Object > listOfObject = new ArrayList< Object >();
List< String > listOfString = new ArrayList< String >();
List< Integer > listOfInteger = new ArrayList< Integer >();
listOfAnyType = listOfString; //legal
listOfAnyType = listOfInteger; //legal
listOfObjectType = (List< Object>) listOfString; //compiler error - in-convertible types   Your Comment




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