Judge exist: a collection of name .contains (content) have returned true
linkedList method:
.addFirst (content): Add the first content
.addLast (content): add one last thing
.getFirst (): returns the first element of the list
.getLast (): Returns the last element of the list
.removeFirst (): Removes the first element
.removeLast (): Removes the last element
Map method:
.put ( "key", "value"): to add paper-cut
.size (): check the number of
.containsKet ( "key"): Is there a key to view this collection
.containsValue ( "value"): Is there a value to view this collection
.keySet (): get all the key
.values (): get all the values
Is a collection of reference data type int is the basic type of data to a collection of <> put int int use of Objiect wrapper class
There are only Iterator iterator Collection
.hasNext (): determines whether there is a
.next (): get the next