What is the difference between Collection and List in Java

Question

What is the difference between Collection and List in Java  When should I use which

User · Answer

List and Set are two subclasses of Collection.

In List, data is in particular order.

In Set, it can not contain the same data twice.

In Collection, it just stores data with no particular order and can contain duplicate data.

User · Answer

Collection is the root interface to the java Collections hierarchy   List is  one sub interface which defines an ordered Collection  other sub interfaces are  Queue which typically will store elements ready for processing  e g  stack    The following diagram demonstrates the relationship between the different java collection types

User · Answer

Collection is the main interface of Java Collections hierarchy and List Sequence  is one of the sub interfaces that defines an ordered collection

User · Answer

First off  a List is a Collection  It is a specialized Collection  however   A Collection is just that  a collection of items  You can add stuff  remove stuff  iterate over stuff and query how much stuff is in there   A List adds the information about a defined sequence of stuff to it  You can get the element at position n  you can add an element at position n  you can remove the element at position n   In a Collection you can t do that   the 5th element in this collection  isn t defined  because there is no defined order   There are other specialized Collections as well  for example a Set which adds the feature that it will never contain the same element twice

User · Answer

Collection is the Super interface of List so every Java list is as well an instance of collection  Collections are only iterable sequentially  and in no particular order  whereas a List allows access to an element at a certain position via the get int index  method

User · Answer

Java API is the best to answer this  Collection     The root interface in the collection   hierarchy  A collection represents a   group of objects  known as its   elements  Some collections allow   duplicate elements and others do not    Some are ordered and others unordered    The JDK does not provide any direct   implementations of this interface  it   provides implementations of more   specific subinterfaces like Set and   List  This interface is typically used   to pass collections around and   manipulate them where maximum   generality is desired    List  extends Collection      An ordered collection  also known as a   sequence   The user of this interface   has precise control over where in the   list each element is inserted  The   user can access elements by their   integer index  position in the list     and search for elements in the list       Unlike sets  lists typically allow   duplicate elements  More formally    lists typically allow pairs of   elements e1 and e2 such that   e1 equals e2   and they typically   allow multiple null elements if they   allow null elements at all  It is not   inconceivable that someone might wish   to implement a list that prohibits   duplicates  by throwing runtime   exceptions when the user attempts to   insert them  but we expect this usage   to be rare

User · Answer

Collection is a high-level interface describing Java objects that can contain collections of other objects   It s not very specific about how they are accessed  whether multiple copies of the same object can exist in the same collection  or whether the order is important   List is specifically an ordered collection of objects   If you put objects into a List in a particular order  they will stay in that order   And deciding where to use these two interfaces is much less important than deciding what the concrete implementation you use is   This will have implications for the time and space performance of your program   For example  if you want a list  you could use an ArrayList or a LinkedList  each of which is going to have implications for the application   For other collection types  e g  Sets   similar considerations apply

[java] What is the difference between Collection and List in Java?

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