Java class Library collection and collections

The difference between Collection and collections in Http://www.cnblogs.com/dashi/p/3597937.htmlJava 1, Java.util.Collection is a Collection Interface (a top-level interface of a collection Class)。 It provides a common interface method for basic manipulation of collection objects. The collection interface has many specific implementations in the Java class Library. The meaning of the collection interface is to provide a maximum unified operation for a variety of specific sets, and its direct inheritance interface has a list and set. Collection
├list
│├linkedlist
│├arraylist
│└vector
│└stack
└set 2, Java.util.Collections is a wrapper class (Tool class/helper Class). It contains a variety of information about collection operations. static Polymorphic method。 This class cannot instantiate, just like a a tool class, which is used to sort, search, and line Cheng the elements in the collection, serving the collection framework of Java.

code example:

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import java.util.ArrayList;import java.util.Collections;import java.util.List;public class TestCollections {         public static void main(String args[]) {        //注意List是实现Collection接口的        List list = new ArrayList();        double array[] = { 112, 111, 23, 456, 231 };        for (int i = 0; i < array.length; i++) {            list.add(new Double(array[i]));        }        Collections.sort(list);        for (int i = 0; i < array.length; i++) {            System.out.println(list.get(i));        }        // 结果：23.0 111.0 112.0 231.0 456.0    }}

Java class Library collection and collections (GO)