Java Reference types

Java Reference types

• To create new data types, complex data types, containing simple primitives or other complex data types you must create a class.
• Reference type can refer to a created object out of a such class or can refer to an array object containing many elements of the same type.
• They are called reference types because they "refers to" data type that is often large.
  Java Reference example:

  ...
  Foo myFoo = new Foo( );    // The new keyword creates a object of class type Foo 
                             // myFoo is a reference-type variable that holds a 
                             // reference to the newly constructed Foo object
  Foo anotherFoo = myFoo;    // There are now two identical references: 
                             // "myFoo" and "anotherFoo"
  
  int i=20;
                            // In this case method1 and method2 are defined 
                            // in the Foo class
  myFoo.method1( myFoo );   // Object (myFoo) are always  passed to 
                            // methods by reference
  myFoo.method2( i );       // Primitive are passed to methods by values
  ...