Java OO Object-oriented attention point one

1.java Idea of purpose

All things are objects, and objects are produced by concern.

A class is an extract of an object that is an instance of a class.

The three major features of 2.javaOO:

Encapsulating inherited polymorphic Abstractions

3 Properties and Behavior

attribute: Refers to what value data the object has.

Behavior: Is what the object can do, or what we want these objects to do.

Usage is: Class variable name = new Class ();

variables, attributes;

Variable. method ();

4. Construction Party:

A. role: Generating Objects

　　B. details:① If a class does not have a write construct,the JVM will give it a default public parameterless construct.

　　　　　　② Once a developer has written a construction method, theJVM does not provide a default construct.

　　C. syntax: The ① method name must be consistent with the class name.

　　　　　　The ② constructor method does not have a return type. (Not even void )

　　D. implementation steps:

　　　　　　① Dividing Space

　　　　　　② attribute in this space

　　　　　　③ to initialize a property

　　　　　　④ executes the code of the writing inside of our re-structuring method

5. Standard JavaBean:

　　A. attribute --The variable property is private, and the corresponding get,Set method is written. ( in Eclipse,theboolean type is changed to get )

　　B. construction -- There must be a public non-parametric structure.

　　C. The final writing of functional methods.

Ta.setage (Ta.getage () + 1); Implement the Age attribute increment of Ta object

6. three ways to Change program control:

　　A. invocation of a method

　　B. SELECT statements

　　C. Looping statements

7. There are three cases when the method is executed:

　　A. method returns a value

　　B. method does not return a value

　　C. method throws an exception

data transfer in 8.Java:

　　in Java, only value is passed, and the base data type is stored in a different way than the reference data type.

9.java and Memory:

memory is divided into Heap , Stack , Data Segment , Code Snippet four areas.

　　A. local variable re-stack area

　　B.new out in the heap area

　　C. string constant re-data segment

use of 10.this:

　　A. for properties, methods, This now refers to the current object

int a = This.age; Property

This.mail (); Method

　　B. call another constructor of this class in one of the constructor methods to achieve the code reuse of the construction method

This ();

This (age);

Note:this () can only be written in the first sentence of this class of construction method

One. array of reference types:

　　A. syntax:

element type [] Array name = new element type [length];

Student [] allstus = new Student [5]; Initializing an array

Allstus[0] = new Student (); Initializing a reference type element

Allstus[0].setname ("Zhang San"); Set method Assignment Value

　　 B. There are two ways to declare an array as a formal parameter:

　　　　① Traditional Way []-- callers can only pass array objects in

ChangeCase (a[]);

}

public static void Changecse (char [] array) {

　　　　the new way after ②jdk1.5 ... - the caller can either pass an array object or pass any number of array elements in

　　ChangeCase (' W ', ' O ', ' r ', ' L ', ' d ');

}

public static void Changecse (char ... array) {

Java OO Object-oriented attention point one