APCS vocab- Lecture notes 1-5

A value we pass to an object’s method is called an argument.

An object’s behavior is determined by instructions within its methods.

Compiling is the process of converting a program written in a high-level language into the bytecode language the Java interpreter understands. A Java compiler will generate a bytecode file from a source file if there are no errors in the source file.

A programmer writes the text of a program using a software program called an editor.

To instruct an object to perform a task, we send a message to it.

n Java, we refer to these messages as methods.

Suppose we take the DrawingTool and create an object myPencil. In OOP terminology, we say the object myPencil is an instance of the DrawingTool class. An object can only be an instance of one class.

The text of a program in a particular programming language is referred to as source code

Attributes are aspects of an object that describe it. The attributes of a pencil are its drawing color, width of the line it draws, its location on the drawing surface, etc. Anything that describes an object is called an attribute

3. In order to use an object within a program, we need to provide a definition for the object. This definition is called a class. The class describes how the object behaves, what kind of information it contains, and how to create objects of that type. A class can be thought of as a mold, template, or blueprint that the computer uses to create objects.

A constructor is a method with the same name as the class.

To see if the mutators worked correctly, we
use other messages to access the object’s
state (called accessors):

Values passed to a method when it is invoked
are called arguments or actual parameters.

The combining of data and behavior into a
single software package is called
encapsulation.

Parameters listed in a method’s definition are called formal
parameters.

An object has its own unique identity, which
distinguishes it from all other objects in the
computers memory.
An objects identity is handled behind the scenes
by the JVM and should not be confused with the
variables that might refer to the object.
When there are no variables the garbage
collector purges the object from memory.

The lifetime of a variable is the period
during which it can be used.
Local variables and formal parameters exist
during a single execution of a method.

Messages that change an object’s state are
called mutators (or modifiers).
To see if the mutators worked correctly, we
use other messages to access the object’s
state (called accessors):

A class is a software package or template
that describes the characteristics of similar
objects.

An object is a run-time entity that contains
data and responds to messages.