Arrays 
Strings
==========================================================
Collection Framework
(ArrayList, HashSet, HashMap)

ArrayList:
==========
its a growable array (dynamic array)
insertion order
duplicates are allowed
Hetrogenious objects are allowed


we have an add method to add an element to Arraylist
how to get size of ArrayList
.size() method
=========================================================
public class Sample {

	public static void main(String[] args) throws NumberFormatException, IOException {
		
		ArrayList obj=new ArrayList();
		obj.add(123);
		obj.add("Sunil");
		obj.add(89.77);
		obj.add(1000);
		
		System.out.println(obj);
		
	}

}
==============================================================
HashSet
=============
it doesnt support duplicate elements
insertion order not preserved
it uses hashing technique to get elements
HashSet internally HashMap
it supports hetrogenious elements

HashSet<Integer> hs=new HashSet<>()
hs.add(10)
=====================================================================
HashSet<Integer> hs=new HashSet<>();
		hs.add(10);
		hs.add(10);
		hs.add(20);
		hs.add(30);
		hs.add(30);
		hs.add(40);
		hs.add(null);
		System.out.println(hs.size());
		System.out.println(hs);
===================================================================
HashMap:
========
we can store records in form of key and value
null also allowed as key
duplicate keys are not allowed 

loadfactor = oldsize+3/2*oldsize
=======================================
put() -----> to insert a record
get() -----> to get the value of particular key
containsKey() ----> to check wheather given key is there or not
size() --------> Number of records
================================
package basic;

import java.io.IOException;
import java.util.HashMap;
//Prime number

public class Sample {

	public static void main(String[] args) throws NumberFormatException, IOException {
		
	HashMap<Integer,String> hm=new HashMap<>();
	hm.put(11,"Sunil");
	hm.put(12, "Vishal");
	hm.put(13,"Abhidutta" );
	hm.put(14, "Nethu");
	hm.put(14, "Kiran");
	hm.put(null, "Null value");
	hm.put(null, "Null value 300");
	
	System.out.println(hm);
	System.out.println(hm.get(12));
	System.out.println(hm.get(13));
	System.out.println(hm.containsKey(10));
	System.out.println(hm.size());
		
	}

}
======================================================================