Source: http://pages.cs.wisc.edu/~bahls/cs302/PrimitiveVsReference.html
- primitive types are the basic types of data
byte, short, int, long, float, double, boolean, char- primitive variables store primitive values
- reference types are any instantiable class as well as arrays
String, Scanner, Random, Die, int[], String[], etc.- reference variables store addresses
- copies the contents of RHS variable into LHS variable
- primitives: the primitive value is copied
- references: the address is copied
- implications: for references the object is not copied, it is shared (reference variables are aliases)
- compares the contents of the variables
- primitives: the primitive values are compared
- references: the addresses are compared
- implications: for references the contents of the objects are not compared
- terminology:
- formal parameter: the parameter variable that is listed (along with its type) in the method declaration
- actual parameter: the parameter that is given when the method is called
- copies the contents of actual parameter into the formal parameter (i.e., pass-by-value)
- primitives: the primitive value is copied
- references: the address is copied
- implications: for references the object is not copied, it is shared (i.e., actual parameter and formal parameter are aliases)
- primitives: changing the formal parameter's value doesn't affect the actual parameter's value
- references: changing the formal parameter's address doesn't affect the actual parameter's address but changing the formal parameter's object does change the actual parameter's object since they refer to the same object
- returns a result to where the method was called
- primitives: the primitive value is returned
- references: the address is returned
- recall: local variables and parameters are destroyed when the method finishes execution
- implications: a locally created object can survive if it is returned or if it is stored in a data member