Study guide: Object-oriented language basics, Part 1
Brush up on Java terms, learn tips and cautions, and review homework assignments
By Jeff Friesen, JavaWorld.com, 04/06/01
Glossary of terms
- behaviors
- Activities that some entity (such as a car) is capable of performing. Also known as functions.
- class
- Source code blueprint for objects.
- class instance
- A synonym for object.
- creation operator
- The
new keyword, which allocates an object's memory and initializes that memory to default values. Note: The Java Language Specification does not refer to new as an operator. However, many developers do refer to new in that capacity.
- doclets
- Small documentation programs that the Javadoc tool processes.
- dot operator
- The period character (
.). Note: The Java Language Specification does not refer to the period character as a dot operator. Instead, the JLS refers to it as a separator because it separates a class name or a reference variable name from a field variable or a method.
- encapsulation
- A primary object-oriented programming principle. The integration of state variables and behaviors into objects.
- functions
- Named bodies of code.
- information hiding
- A concept that facilitates program maintenance by hiding state variables and behaviors that don't need to be externally accessed.
- object
- A class instance.
- pointers
- Variables that contain the addresses of other variables.
- references
- Abstract object identifiers.
- starting class
- The first program class that the JVM loads.
- state
- The data values of some entity.
Tips and cautions
These tips and cautions will help you write better programs and save you from agonizing over why the compiler produces error
messages.
Tips
- You might find it helpful to visualize objects as circles that are referenced by reference type variables.
Cautions
- You cannot use a reserved word to name a class. If you do, the compiler reports an error.
- The compiler reports an error if you declare two or more classes (in the same source file) with keyword
public.
- Attempts to create objects from abstract classes result in compiler errors.
Homework
Read what The Java Language Specification says about classes and objects.
Experiment with the javadoc tool and explore the SDK documentation to find out what it has to say about javadoc.