LinkedHashMap:
Hash table and linked list implementation of the Map interface, with predictable iteration order. This implementation differs from HashMap in that it maintains a doubly-linked list running through all of its entries. This linked list defines the iteration ordering, which is normally the order in which keys were inserted into the map (insertion-order). Note that insertion order is not affected if a key is re-inserted into the map.
package com.candidjava.core;
import java.util.LinkedHashMap;
public class LinkedHashMapExample {
public static void main(String[] args) {
LinkedHashMap<String,String> hm=new LinkedHashMap<String,String>();
hm.put("name","candid");
hm.put("email","[email protected]");
hm.put("password", "123456");
hm.put("street", "shanthi nagar");
hm.put("password", "789");
hm.put(null, "chennai");
hm.put(null, "Delhi");
hm.put("altemail", null);
hm.put("altph", null);
System.out.println("LinkedHashMap .. "+hm);
System.out.println("size ... "+hm.size());
}
}Output:
LinkedHashMap .. {name=candid, [email protected], password=789, street=shanthi nagar, null=Delhi, altemail=null, altph=null}
size ... 7