Shulou(Shulou.com)06/02 Report--

This article will explain in detail how to analyze modifier modifiers, the content of the article is of high quality, so the editor will share it for you as a reference. I hope you will have a certain understanding of the relevant knowledge after reading this article.

Modifier Summary Modifiers

The function modifier always precedes the return value type!

The variable modifier always precedes the variable type!

ClassModifier: one of

Annotation public protected private

Abstract static final strictfp

External classes: cannot be modified by protected, private, static and final

Member inner class: both are fine

Non-member inner class: none is allowed

FieldModifier: one of

Annotation public protected private

Static final transient volatile

MethodModifier: one of

Annotation public protected private

Abstract static final synchronized native strictfp

ConstructorModifier: one of

Annotation public protected private

InterfaceModifier: one of

Annotation public protected private

Abstract static strictfp

VariableModifier: one of

Annotation final

Class field method constructor interface variable

Annotation √ √

Public/protected/private √ ×

Abstract/strictfp √ × √ × √ ×

Static √ × √ ×

Final √ × × √

Transient/volatile × √ × × ×

Synchronized/native × × √ × × ×

Annotation

All of the above is fine.

Public/protected/private

Permission modifier, except variable can be-> frequently tested.

Abstract/strictfp

Class/interface/method

Static

Except for constructor and variable, you can take the regular exam.

Final

Except for constructor and interface.

Transient/volatile

Can only modify field

Synchronized/native

Can only modify method

Final and abstract are in conflict.

/ *

Summary of access permissions for members and constructors between packages:

Public protected has no modifier private

Ok ok ok ok in the same class

Ok ok ok in the same package

Different package * subclass ok ok

Ok in different packages

Prerequisite for different package member access: the accessed class must be public, and the accessed member must be public

Subclasses in different packages can also directly access members and constructors of protected in the parent class.

There are two levels of permission restrictions for different package access:

The first layer is the permission restriction of the class, and the permission of the class can be public/ unauthorized modifier.

The second layer is the permission restriction of members. The permissions of members can be public/protected/ No permission modifier / private and so on.

Access must be allowed by the permissions of the class before considering whether the permissions of members are allowed to access!

In actual programming, the classes accessed are generally of different packages:

The class is public and the constructor is public

Allow objects to be created by classes with different packages; otherwise, objects are not allowed to be created by classes with different packages

The class is public and the constructor is protected

Only classes with different packages are allowed to inherit (designed to be inherited, and objects are not allowed to be created by classes with different packages)

The class is public and the constructor is private (usually final)

It is not allowed to create objects (including the classes in this package). In this case, the public method is generally provided to get the objects of the class.

In different packages, the role of protected is to restrict members and constructors to be accessed by subclasses

In the same package, protected has no effect when modifying member variables and constructors, but only overrides member functions.

, /

On how to analyze the modifier modifier to share here, I hope the above content can be of some help to you, can learn more knowledge. If you think the article is good, you can share it for more people to see.

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.