Use of ArrayList

Arraylistdemo

 PackageCn.stat.p6.arraylist.demo;Importjava.util.ArrayList;ImportJava.util.Iterator;ImportCn.stat.p5.person.demo.PresonDemo; Public classArraylistdemo {/**     * @paramargs*/     Public Static voidMain (string[] args) {//TODO auto-generated Method StubArraylist<presondemo> al=NewArraylist<presondemo>(); Presondemo P1=NewPresondemo ("List1", 11); Presondemo P2=NewPresondemo ("List2", 12); Presondemo P3=NewPresondemo ("List3", 13);     Al.add (p1);     Al.add (p2);      Al.add (p3); Al.add (NewPresondemo ("List5", 15)); Iterator<PresonDemo> it=Al.iterator ();  while(It.hasnext ()) {Presondemo P=(Presondemo) it.next (); System.out.println (P.getname ()+";;" +p.getage ()); } Show (3); String QC= "123"; String AI= "12";      System.out.println (Ai.hashcode ());          System.out.println (Qc.hashcode ()); }     Public Static voidShowinti) {intS=i+1;            System.out.println (s); }        }

Presondemo

 PackageCn.stat.p5.person.demo; Public classPresondemoImplementsComparable {PrivateString name; Private intAge ; /**     * @paramargs*/     PublicString GetName () {returnname; }     Public voidsetName (String name) { This. Name =name; }     Public intGetage () {returnAge ; }     Public voidSetage (intAge ) {         This. Age =Age ; }     Public voidOutprint () {System.out.println ( This. age+ ".." + This. Name); }     PublicPresondemo (String name,intAge ) {             This. Name =name;  This. Age =Age ; }    //TreeSet (); For empty, real-class internal comparators@Override Public intcompareTo (Object o) {//TODO auto-generated Method StubPresondemo p=(Presondemo) o; if(p.age< This. Age)return1; if(p.age> This. Age)return-1; return0; }}

Use of ArrayList