R

raw type

A parameterized type invoked without its parameter. ArrayList<E> is a parameterized type. You can either supply a parameter for E, or you can forget about it, in which case your invocation is ArrayList aList = new ArrayList();, and aList is then referred to as a raw type.

reference

A data element (object or interface) that serves as a pointer to an address in memory where the object is stored. A reference variable is a name used to reference a particular instance of a Java class.

return

A Java keyword used to indicate that a method has completed execution, and should give control back to the caller. return is optionally followed by a value or expression as required by the method definition. The following are all legal: return;, return "choppers";, return (x < (7 + y));, and return new Double(42);.

runtime

though “at runtime” is sometimes used to mean “during execution of the program.”

See also [Java Runtime Environment]