"Hello, World" in Java

• Construct new objects with new operator
  

  new Greeter("World")
  

  • new allocates memory for new object and invokes object constructor
  • constructor is a method with the class name used to initialize new objects
  • a class may have several constructors, with different parameter lists (overloading)

  • default constructor takes no parameters. E.g.
    

      public Greeter()
      {
          name = "Java";
      }

• Can invoke method on newly constructed object
  

  new Greeter("World").sayHello()
  

• More common: store object reference in object variable
  

  Greeter worldGreeter = new Greeter("World");
  

• Then invoke method on variable:
  

  String greeting = worldGreeter.sayHello();