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40 Cards in this Set
- Front
- Back
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object
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Java objects model objects from a problem domain
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class
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Objects are created from classes. The class describes the kind of object; the objects represent individual instantiations of the class
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method
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We can communicate with objects by invoking methods on them. Objects usually do something if we invoke a method
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parameter
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Methods can have parameters to provide additional info for a task
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signature
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The header of a method is called its signature. It provides info necessary to invoke that method
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type
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Parameters have types. The type defines what kind of values a parameter can take
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multiple instances
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Many similar objects can be created from a single class
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state
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Objects have state. The state is represented by storing values in fields
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method-calling
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Objects can communicate by calling each other's methods
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source code
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The source code of a class determines the structure and behaviour (the fields and methods) of each object of the class
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result
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Methods may return info about an object via a return value
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field
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Fields store data for an object to use. Fields are also known as instance variables
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comment
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Comments are put into class source code to provide explanations to human readers
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constructor
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Constructors allow each object to be set up properly when it is first created
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scope
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The scope of a variable defines the section of source code from where the variable can be accessed
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lifetime
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The lifetime of a variable describes how long the variable continues to exist before it is destroyed
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assignment
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Assignment statements store the value represented by the right-hand side of the statement in the variable named on the left
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method
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Methods have two parts - a header and a body
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accessor method
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Accessor methods return info about the state of an object
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mutator method
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Mutator methods change the state of an object
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conditional
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A conditional statement takes one of two possible actions based upon the results of a test.
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boolean expression
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Booleans can have one of two possible values - true or false.
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local variable
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A local variable is a variable declared and used within a single method. It's scope and lifetime are limited to that of the method.
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abstraction
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Abstraction is the ability to ignore details of parts to focus attention on a higher level of a program
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modularization
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Modularization is the process of dividing a whole into well-defined parts which can be built and examined separately, and which interact in well-defined ways
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classes define types
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A class name can be used as the type for a variable. Variables that have a class as their type can store objects of that class
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class diagram
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The class diagram shows the classes of an application and the relationships between them. It gives info about the source code. It presents the static view of a program
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object diagram
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The object diagram shows the objects and their relationships at one moment in time during the execution of an application. It gives info about objects at runtime. It represents the dynamic view o a program
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object references
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Variables of object types store references to objects
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primitive type
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The primitive types in Java are the non-object types. Types such as int, boolean, char, double and long are the most common primitive types. Primitive types have no methods
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object creation
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Objects can create other objects using the new operator
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overloading
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A class may contain more than one constructor, or more than one method of the same name, as long as each has a distinctive set of parameter types
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internal method call
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Methods can call other methods of the same class as part of their implementation. This is called an internal method call
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external method call
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Methods can call methods of other objects using dot notation. This is called an external method call
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debugger
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A debugger is a software tool that helps in examining how an application executes. It can be useful to find bugs
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collections
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Collection objects are objects that can store an arbitrary number of other objects
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loop
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A loop can be used to execute a block of statements repeatedly without having to write them multiple times
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iterator
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An iterator is an object that provides functionality to iterate over all elements of a collection
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null
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The Java reserved word null is used to mean 'no object' when an object variable is not currently referring to a particular object. A filed that has not explicitly been initialized will contain the value null by default
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array
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An array is a special type of collection that can store a fixed number of elements
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