2-Write your own hashmap

 Public classEntry {//Key    PrivateObject Key; //value    PrivateObject value; //Constructors     PublicEntry (Object key, Object value) {Super();  This. Key =key;  This. Value =value; }     PublicObject GetKey () {returnkey; }     Public voidSetkey (Object key) { This. Key =key; }     PublicObject GetValue () {returnvalue; }     Public voidSetValue (Object value) { This. Value =value; }}

 Public classHashMap {//storing an array of elements    Privateentry[] Entry =NULL; //Record Map number    Private intsize; //Constructors     PublicHashMap () { This. Entry =Newentry[100]; }        //Add new elements     Public voidput (object key, Object value) {Entry e=NewEntry (key, value); Entry[size]=e; Size++; }    //get Element     Publicobject get (Object key) { for(inti = 0; i < size; i++) {Entry e=Entry[i]; Object k=E.getkey (); if(Key.equals (k)) {returnE.getvalue (); }        }        return NULL; }}

Code testing

 Public class Demo {    /***     *     simple put get method @param  args     */ Public    staticvoid  main (string[] args) {        HashMap map=New  HashMap ();                Map.put ("Liu Shihua", "Roland");                 = Map.get ("Liu Shihua");                System.out.println (s);    }}

2-Write your own hashmap