User application

Introduction

Application program refers to a computer program for accomplishing one or more specific tasks. It runs in user mode, can interact with users, and has a visual user interface. Applications are usually divided into two parts: Graphical User Interface (GUI) and Engine (Engien), which is different in concept from application software. Application software refers to the classification of the purpose of use, which can be a single program or a collection of other subordinate components, such as Microsoft Office and OpenOffice. Application refers to a single executable file or a single program, such as Word, Photoshop. In daily life, the two are not carefully distinguished. The program is generally regarded as an integral part of the software.

For example: a game software includes programs (such as *.exe on the windows platform, *.app on the mac osx platform, etc.) and other pictures (*.bmp, etc.), sound effects (*.wav, etc.), etc. Attachments, then this program is called "application", and it is collectively called "software" together with other files (pictures, sound effects, etc.).

Run Mode

Application (Application) runs in user mode. It can interact with the user and generally has a visual user interface.

What you need to know about applications is: each application runs in an independent process, and they have their own independent address space. The dividing line between different applications is called the process boundary.

Extension

Flickr is one of the first web services to use tagging as a sorting and search mechanism on a large scale, but it seems that its parent company Yahoo believes that this legacy is not enough to make this The photo-sharing service maintains the pace of development; this latest adjustment is also consistent with the retro filter and @-username adopted by the Flickr application. However, the hashtags have not been extended to the entire Flickr website, and the existing tags in the application have not become clickable hashtags.

By shifting to this application-driven mobile Internet, the Flickr application has become similar to Twitter and Instgram, but this is actually not a very big change-once you click on a tag, you You will see a series of related photos, just like a normal search. In addition, the way this service operates has not changed significantly, but mobile users can more easily find photos related to the photos they are viewing.

Level distinction

For windows operating system:

1. Windows compatible

The application can run on Windows .NET Server and Windows 2000

2. Designed Windows .NET Server OS certification for Windows XP (customer)

The application program has the above logo and passed the relevant certification program

3. Make full use of the features and functions provided by the operating system

Provide applications that meet user needs with minimal code and time

User application classification

Office Software

Word processor, spreadsheet program, slide report, mathematical program creation editor, drawing program, basic database, file management system, file editor

Instant messaging software, e-mail client, web browser, FTP client, download tool

Multimedia

Media player, image editing software, audio editing software, video editing software, computer-aided design, computer games, desktop publishing

Analysis software

Analysis software

Computer algebra system, statistical software, digital calculation, computer-aided engineering design

Collaborative software

Collaborative product development< /p>

Business software

Accounting software, enterprise workflow analysis, customer relationship management, back office, enterprise resource planning, supply chain management, product life cycle management< /p>

Database

Database management system

Other

Education software , DIY software

Program composition

Game applications are usually divided into two parts: Graphical User Interface (GUI) and Engine (Engine).

Under DOS or Windows, the extension is *.exe or *.com

Under mac os x, the extension is generally *.app

Key Programs

You know which applications will become the target of cybercriminals seeking illegal financial benefits. Therefore, take preemptive action and protect your most risky applications:

• Use a web application firewall to check all financial applications that point to or come from the most vulnerable to known or new attacks Program traffic, and patch specific vulnerabilities in all applications.

• Malware is detected to determine the device being attacked or the signs of blocked connection information-such as the traces of MitB attacks that rapidly manipulate transaction details.

Categories

Introduction

It has several categories, namely: single document, multiple documents, and basic dialog boxes. .

To give you an example, a single document is like a notepad, and there is always a document window in it, and a multi-document window is like Word, which can open multiple document windows at the same time. This is also the most used one now. The dialog box is the simplest, used in the design of the dialog box. Nowadays, it is rarely used simply based on dialog boxes. It is generally used to write instant messaging software, and more often dialog boxes and multi-file windows are used interspersedly.

Six scopes

There are six commonly used scope types in most server-side J2EE applications:

Transaction

HTTP session

Application

Global

None (None)

Transaction scope

The transaction scope covers the entire life cycle of a transaction. This range starts at the beginning of a transaction. At this time, a unique range key is created. This range ends when the transaction is committed or rolled back. At this time, all objects associated with the transaction scope are automatically released back to their pool.

Request scope

The request scope corresponds to the scope of a servlet request; after the container calls the servlet to process the request, the request scope starts immediately. At the same time, a unique range key is created. The request scope ends before the servlet completes processing. At this time, all objects associated with this range are automatically released back to their pool.

HTTP session scope

The HTTP session scope corresponds to the life cycle of an HTTP session. It starts when a new HttpSession is created. At this time, a unique range key is created. It ends when the session is destroyed or expired. At this time, all objects associated with this range are automatically released back to their pool.

Application scope

The application scope covers the entire life cycle of the application. It starts when an application is deployed to an application server. At this time, a unique range key is created. This range ends when the application stops running or is deleted from the application server. At this time, all objects associated with this range are automatically released back to their pool.

Global range

The global range is the largest range. Objects in this range will not be released.

No scope

No scope is used for objects that do not use the object pool. Objects in this range are created through its own object constructor every time and released by the Java garbage collector. The object wrapper does not manage them at all.

Frequently Asked Questions

There are two aspects to this phenomenon: one is the hardware, that is, there is a problem with the memory; the other is the software, which has many problems.

Hardware reasons

Generally speaking, computer hardware is not easy to break. The possibility of memory problems is unlikely (unless your memory is really a mess), the main aspects are:

1. The memory bar is broken (second-hand memory In most cases)

2. Used memory with quality problems

3. The memory is inserted into the golden finger part of the motherboard Too much dust

4. Using different brands of memory with different capacities, resulting in incompatibility

5. The heat dissipation problem of

You can use the MemTest software to test the memory, which can thoroughly detect the stability of the memory.

Software reasons

Let’s talk about the principle first: the memory has a place to store data called the buffer. When the program puts the data in the buffer, it needs the "function function" provided by the operating system. "Apply for the application program. If the memory allocation is successful, the function will return the address of the newly opened memory area to the application program, and the application program can use this memory through this address. This is the "dynamic memory allocation", and the memory address is also the "cursor" in programming. Memory is not always available and inexhaustible, and sometimes memory allocation will fail. When the allocation fails, the system function will return a value of 0. At this time, the return value "0" does not indicate a newly activated cursor, but a notification sent by the system to the application that an error has occurred.

As an application, you should check whether the return value is 0 after each application for memory: if it is, it means that there is a failure and some measures should be taken to rescue it, which enhances the program’s " Robustness". If the application does not check for this error, it will consider this value as an available cursor assigned to it according to "inertia of thinking", and continue to use this memory in subsequent executions. The real 0-address memory area stores the most important "interrupt descriptor table" in the computer system, and it is absolutely not allowed to be used by applications. Under operating systems without protection mechanisms (such as DOS), writing data to this address will cause immediate downtime.

In a robust operating system, such as Windows, this operation will be immediately captured by the system's protection mechanism. As a result, the operating system will forcibly close the faulty application to prevent the error from expanding. At this time, the above-mentioned memory cannot be "read" error will appear, and the referenced memory address is "0x00000000". There are many reasons for the failure of memory allocation failure. Insufficient memory, mismatched version of system functions, etc. may have an impact. Therefore, this kind of allocation failure is more common when the operating system is used for a long time, a variety of applications (including unintentionally "installed" virus programs) are installed, and a large number of system parameters and system files are changed.

In applications that use dynamic allocation, there are sometimes situations like this:

The program tries to read and write a piece of memory that "should be available", but I don’t know why. The cursor that is expected to be available has expired. It may be "forgot" to request allocation to the operating system, or it may be that the program itself has logged out of this memory at some point and "not paid attention", etc. The logged out memory is reclaimed by the system, and its access rights no longer belong to the application. Therefore, read and write operations will also trigger the protection mechanism of the system. The only outcome of an attempted "illegal" program is to be terminated by the operation and reclaim all Resources. The laws of the computer world are still much more effective and stricter than humans! Situations like this are all bugs of the program itself, and you can often reproduce the error in a specific sequence of operations. The invalid cursor is not always 0, so the memory address in the error message is not necessarily "0x00000000", but other random numbers.

Solution

1. Check whether there are Trojan horses or viruses in the system. Such programs often modify the system irresponsibly in order to control the system, causing the operating system to malfunction. Normally, you should strengthen your information security awareness and never be curious about executable programs from unknown sources.

2. Update the operating system, let the installation program of the operating system re-copy the correct version of the system files and modify the system parameters. Sometimes the operating system itself will have a BUG, ​​so please pay attention to installing the official upgrade program.

3. Try to use the latest official version of the application, beta version, trial version will have BUG.

4. Delete and recreate the files in the Winnt\System32\Wbem\Repository folder: Right-click My Computer on the desktop, and then click Manage. Under "Services and Applications", click Services, and then shut down and stop the Windows Management Instrumentation service. Delete all files in the Winnt\System32\Wbem\Repository folder. (Please create a backup copy of these files before deleting.) Open "Services and Applications", click Services, then open and start the Windows Management Instrumentation service. When the service restarts, these files will be recreated based on the information provided in the following registry key: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WBEM\CIMOM\Autorecover MOFs.