difference between equals&& = = operator ?

//StringMethodsDemo for equals() && = =
class  StringMethodsDemo
{
};
//StringMethodsDemoImpl
class  StringMethodsDemoImpl
{//main()
public static void main(String[] args)
{
StringMethodsDemo  stringMethodsDemo=new StringMethodsDemo();
String string1=new String("hello");//String class object
String string2=string1;
String string3=new String("hello");//String class object

System.out.println(string1==string2);
System.out.println(string1.equals(string2));
}
}

out put:

D:\anvesh_java>java StringMethodsDemoImpl
true
true