CSC 335 - Java Basics

Primitive Types

Types built into the language, such as integers and floats, referenced by value.

Reference Types

Types that contain a reference to the object itself when variables are created.

Alias

Two variables that refer to the same reference.

New

Java keyword that allocates memory for a new object on the heap.

Class

Defines an object by specifying its data (fields) and methods.

Dereferencing

Accessing an object’s data or methods through the object name.

Instance

An individual object of a class, e.g., "studentOne" is an instance of the Student class.

Static Method

A class-defined method that does not require an object of that class type to be used.

Static Variable

A member variable common to all objects of a class.

Change a Static Variable

Use a static method call to change a static member, affecting all objects of that class.

Private Keyword

An access modifier that restricts use to the declaring class.

Public Keyword

An access modifier that allows free use by other classes.

Global Variables

Variables declared outside of any methods, accessible from anywhere in the program.

Final Keyword

A non-access modifier used to restrict what can be done to a variable, method, or class.

Final Variable

A constant variable that cannot be changed once initialized.

Final Method

A method that cannot be overridden by subclasses.

Final Class

A class that cannot be inherited or extended.

Global Variable/Static Instance Variable should be_____.

Should be non-writable to prevent editing.

No Global Variables

Expected practice in CSC 335; global constants like PI are acceptable.

Default Visibility

Used when no access modifier is specified, making something visible within the package.

Protected Keyword

Makes something visible within the package and to any subclasses.

Instance Method

A method that belongs to an object, specifying its interactions.

Import Statement

Used to reference classes in a package for simpler naming.

Fully Qualified Name

The complete package-prefixed name of a class or method.

Parametric Polymorphism

Ability for a single variable to work with multiple types.

Diamond Operator

Used when instantiating generic class objects, e.g., ArrayList.

Collections Framework

A set of classes related to Collection-type objects.

Set

A collection that does not allow duplicate values.

List

A sequence where each item has a position.

Map

A collection of key-value pairs.

HashSet

An implementation of the Set interface backed by a hashtable.

ArrayList

An implementation of the List interface backed by an array.

HashMap

An implementation of the Map interface backed by a hashtable.

TreeMap

An implementation of the Map interface backed by a red-black tree.

Throwable

The root of the exception hierarchy, superclass of all errors and exceptions.

Throw Keyword

Used for explicitly throwing a single exception.

Throws Keyword

Denotes that a method can throw a specific exception.

Try/Catch

Keywords used to handle exceptions in a block of code.

Inherit from One Parent Class

Java does not support multiple inheritance.

Object Class

All classes in Java automatically extend this class if no other is specified.

Equals Method

Compares references to determine if two objects are the same.

toString Method

Returns a String representation of an object.

HashCode Method

Returns a hash value (integer) for an object.

Polymorphism

The ability for something to take on multiple forms in Java.

Overloading

Methods or operators with multiple definitions but the same name.

Parameter Coercion

Implicitly changing an argument to fit the expected type.

Subtype Polymorphism

Created through inheritance, allowing methods expecting a parent type to work with child types.