1.Collection 和 Collections
首先Collection和Collections是两个完全不同的范畴。正如下图，Collection是所有集合的root接口,而Collections仅仅是一个工具类，它提供了很多静态的工具方法来操作一个集合。
2. 集合的继承树
3.Map的继承树
4.总结
5.示例代码
Code:
List<String> a1 = new ArrayList<String>();
a1.add("Program");
a1.add("Creek");
a1.add("Java");
a1.add("Java");System.out.println("ArrayList Elements");System.out.print("\t" + a1 + "\n");
List<String> l1 = new LinkedList<String>();
l1.add("Program");
l1.add("Creek");
l1.add("Java");
l1.add("Java");System.out.println("LinkedList Elements");System.out.print("\t" + l1 + "\n");
Set<String> s1 = new HashSet<String>(); // or new TreeSet() will order the elements;
s1.add("Program");
s1.add("Creek");
s1.add("Java");
s1.add("Java");
s1.add("tutorial");System.out.println("Set Elements");System.out.print("\t" + s1 + "\n");
Map<String, String> m1 = new HashMap<String, String>(); // or new TreeMap() will order based on keys
m1.put("Windows", "2000");
m1.put("Windows", "XP");
m1.put("Language", "Java");
m1.put("Website", "programcreek.com");System.out.println("Map Elements");System.out.print("\t" + m1);
Output:
ArrayList Elements
[Program, Creek, Java, Java]
LinkedList Elements
[Program, Creek, Java, Java]
Set Elements
[tutorial, Creek, Program, Java]
Map Elements
{Windows=XP, Website=programcreek.com, Language=Java}
