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Java 2 Programmers Certification - Glossary

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This series provides an overview of the Java programming language. It prepares the experienced Java programmer for the Java 2 Programmer Certification Exam
  1. 1Z0-803
  2. 1Z0-804
Topics include object orientation, the statements used to control program flow and exception handling, the classes and interfaces of the java.lang package and the java.util package, the development of Java-based GUI, and the methods and tools for performing sophisticated input and output operations.
Absolute value
The absolute value of a negative number is the number multiplied by -1. The absolute value of a non-negative number is the same as the number.
Abstract method
A method whose implementation is deferred to a subclass.
Access modifier
A modifier that is used to limit access to a class, class member, or constructor.
Automatic variable
A variable whose scope is limited to a code block within a method. Automatic variables are also referred to as local variables.
Blocking on I/O
Waiting for an I/O operation to be completed.
Cast
To convert from one type to another.
Catch or declare rule
If an exception can be thrown during the execution of a method then the method must either catch the exception or declare it in the method's throws clause.
Class
A template for the creation of objects.
Classification
The organization of information into hierarchical categories.
Clipping
Painting to an area that is restricted by a geometric shape, usually a rectangle.
Compilation unit
A source code file.
Component
A GUI element.
Constant
A variable whose value is final and cannot be changed.
Constructor
A special method that is used to create objects as instances of a class.
Container
A component that is used to collect, organize, and display other components.
Context Switching
When a CPU switches from executing one thread to executing another, the CPU needs to save the local data and program pointer of the current thread, and load the local data and program pointer of the next thread to execute.
This switch is known as a context switch. The CPU switches from executing in the context of one thread to executing in the context of another thread.
Context switching requires resources and you do not want to switch between threads more than is necessary.
Current object instance
The current object that is being executed.
Degree
A unit of angular measurement.
Deprecated
In the process of being removed from the Java language or API.
Deserialization
Reading an object from a stream.
Dimensions
The size of an array.
Direct or random access I/O
I/O that is performed to or from direct locations of a file.
Direct superclass
The class that is identified in a class's extends clause. If a class is declared without an extends clause, then its direct superclass is java.lang.Object.

Dynamic binding
A program compilation and execution feature that allows programs to delay until Runtime decisions about the type of objects that they access.
Eligible for garbage collection
An object that is unreachable is eligible to be destroyed and have its resources reclaimed by the garbage collector.
Encapsulation
A quality of classes with well-defined and controlled interfaces.
Enclosing scope
The instance of an outer class in which an instance of an inner class is created.
Enclosing statement
A statement, such as a switch, if, or loop statement, that contains the statement block of the statement in question.
Entry point
The first method that is executed when an application (main()), thread (run()), or applet (init()) is executed.
Event
An object that signals the occurrence of an action.
Event adapter
A class that provides a default implementation of an event listener interface.
Event bubbling
Event bubbling describes the JDK 1.02 event-handling approach. Events are handled by subclassing a component and overriding its event handling methods.
Unhandled events are propogated to a component's container. Event bubbling is also referred to as event inheritance.
Event delegation
Event delegation describes the JDK 1.1 event-handling approach. Event listeners are registered with the source of an event. When an event occurs, the source invokes the event handling functions of its event handlers.
Event inheritance
Event inheritance describes the JDK 1.02 event-handling approach. Events are handled by subclassing a component and overriding its event handling methods. Unhandled events are propogated to a component's container. Event inheritance is also referred to as event bubbling.
Event listener
An object that registers itself to handle the occurrence of an event.
Exception
An object that signals that an abnormal event or error has occurred.
Execution state
The states occupied by a thread during the course of its execution.
Field
Short for field variable.
Field variable
A variable that is a member of a class.
File pointer
A pointer to a location within a file.
Filter
An object that reads one stream, performs an operation on the data that is read, and writes it back out as another stream.
Friendly access
The default access that occurs when no access modifier is specified. Access is restricted to the package in which an item is declared. Also referred to as package access.
Garbage collection
The process by which the memory occupied by unreachable objects is reclaimed.
Glossary
To access all the items in the course glossary, click the Show All Terms button, below.

Hash table
A table which maps elements to their values based upon a hashing algorithm. A hashing algorithm provides a uniform distribution of values over a certain range.
IEEE 754 standard
The IEEE 754 standard is standard for implementing floating-point numbers and floating-point arithmetic.
If condition
The condition that is evaluated as part of an if statement.
Inheritance
The passing on of design information from a superclass to a subclass.
Initializer
A block of code that is used to initialize a variable.
Inner interface
An interface that is declared as a member of another class or interface.
Interface
A collection of methods that are implemented by classes.
Last-in first-out stack
A data structure in which the last element added is the first element retrieved.
Layout manager
An object that is used to organize the way in which components are displayed as part of their container.
Layout policy
The policy used by a layout manager to lay out a container.
Left associative
Operations that are left associative are performed in a left to right manner. That is, x op y op z is evaluated as (x op y) op z.
Local inner class
An inner class that is declared local to a block of code.
Local variable
A variable whose scope is limited to a code block within a method. Local variables are also referred to as automatic variables.
Lock
A mechanism for implementing shared access to an object. Also referred to as a monitor.
Member
An element of a class or interface, such as a field variable, method, or inner class. An element of a package, such as a class, interface, or subpackage.
Member variable
Another name for a field variable.
Method
A member of a class that allows operations to be performed on objects of that class.
Method signature
The name of the method and the number and types of formal parameters to the method.
Modifier
A keyword that is used to modify the definition of a class, variable, method, or constructor.
Monitor
A mechanism for implementing shared access to an object. Also referred to as a lock.
Multiple inheritance
The inheritance of class members from more than one parent.
Multithreaded program
A program that simultaneously supports more than one thread of execution.

Mutually exclusive
Either but not both.
Naming context
A context or scope in which identifiers are unique.
Natural logarithm
A logarithm that is computed using Euler's constant as a base.
Nested class
A class that is declared as a member of another class or interface.
Non-deterministic
Cannot be predicted or determined.
Numeric promotion
The conversion of numeric values to a larger type to support operations on that type.
Object
An instance of a class. A executable unit of code that contains data (field variables) and provides operations for accessing that data (methods).
Order of evaluation
The order in which expressions are evaluated.
Package
A collection of related classes and interfaces that are organized into a separate naming context.
Package access
The default access that occurs when no access modifier is specified. Access is restricted to the package in which an item is declared. Also referred to as friendly access.
Painting
The process of drawing to an area of the screen.
Painting thread
A background thread that determines when a portion of the screen needs to be painted or repainted.
Polar coordinates
Coordinates that are expressed in terms of an angle and radius values.
Polymorphism
Having many forms.
Precedence
The order in which operations are performed.
Preemptive scheduling
An approach to scheduling in which the highest priority thread continues to execute until it enters a wait state or a higher priority thread comes into existence.
Primitive type
One of the following data types: boolean, byte, char, short, int, long, float, and double. Primitive types are collections of values and are not objects.
Radians
A unit of angular measurement.
Random number
A number that is produced by a random number generation algorithm. Random numbers appear to be random.
Right associative
Operations that are right associative are performed in a right to left manner. That is, x op y op z is evaluated as x op (y op z).
Runtime exception
An exception that is thrown by the Java runtime system.
Scheduler
The part of an operating system that assigns threads to CPUs. Also referred to as the thread scheduler.

Scheduling
The assignment of threads to CPUs.
Scope
The extent of the context of a definition.
Serialization
The process of writing an object to a stream.
Serialize
To write to a stream.
Serialized
Written to a stream.
Short-circuit
A boolean operation in which one operand determines the result of the operation.
Signature
The name of the method and the number and types of formal parameters to the method.
Single inheritance
The inheritance of class members from a single parent.
Statement block
A sequence of statements enclosed in brackets.
Static initializer
A block of code that is used to initialize a static variable.
Stream
A sequence of characters or bytes.
Strict subclass
A subclass that is not the class itself.
Subclass
A class that extends another class. All classes are a subclass of themselves.
Superclass
A class that is extended by another class.
Synchronization
The coordination of multi-thread access to shared objects.
Thread
A sequence of statements that is executed as part of a program.
Thread priority
A ranking of threads that determines their likelihood of being scheduled.
Thread scheduler
The part of an operating system that assigns threads to CPUs. Also referred to as the scheduler.
Time slicing
A scheduling approach in which a thread executes for a slice of time and then enters a waiting state while another (possibly same) thread is scheduled.
Top-level class
A class that is not nested or a static inner class.
Trigonometric functions
Functions that relate the lengths of line segments, their ratios, and angle measurements.
Unicode
A 16-bit character set that includes ASCII and provides support for international characters.
Unreachable object
An object that is no longer accessible to a program.
UTF
A variation of Unicode referred to as the Universal Character Set Transformational Format (UTF).
Variable
An identifier of a specific type that is used to store a primitive value or reference an object.
Wrapper classes
Classes of java.lang that encapsulate the primitive types.
Xy-coordinates
The Cartesian coordinate system limited to the xy-plane.
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