scholl concepts

Concurrency Concepts: concurrency (Concurrency) and parallelism (Parallelism)Concurrency is biased toward multiple tasks alternating, and multiple tasks may be sequential. And parallelism is the true "simultaneous execution" of the meaning. In strict terms, multiple tasks in parallel are real and simultaneous, and for concurrency, the process is just alternating, and running task a a little later executes task B, and the system keeps switching between

This article address: http://www.cnblogs.com/archimedes/p/java-study-note3.html, reprint please indicate source address.1. An overview of object-oriented program design methodsObject-Oriented ProgrammingCompared with the structured programming method, it is more in line with the human understanding of the real world thinking mode, has become the mainstream direction of program designKey concepts involved: abstraction, encapsulation, inheritance, polym

position that have been calculated.At the end of the call to the Move method, we passed only the DX and dy two parameters, and do not need to pass the self parameter (because self is for internal use only).My summer can run.Sub-classThe category itself can be further subdivided into sub-classesFor example, birds can be further divided into chickens, geese, oriole.In OOP, we express these concepts through inheritance (inheritance).Class Chicken (Bird)

10 Concepts of Java1 , Initialization of the object(1) Initialization of non-static objectsWhen an object is created, all data members of the class in which the object resides are initialized first.Base type: type int, initialized to 0.If object: These objects are initialized sequentially.The function of the construction method is initialization.(2) Initialization of static objectsThe static variables of the main class in the program are initialized

instantiated before it can be called in the program, a class can instantiate multiple objects, each object can also have different properties, like human refers to everyone, each person refers to the specific object, people and people before there is a common, there are differentInstantiation: The process of producing an object from a class is called instantiation.When the software system is running, the class is instantiated as an object (object) that corresponds to a specific thing and is an

This is a series of articles about Linux systems, which I found in learning Linux.The author introduces this series of articles in this article: In this series of articles I describe the basic concepts of Linux. The Linux operating system inherits from UNIX. An operating system is a set of software that controls and uses computers. UNIX is a set of rules that all UNIX systems obey the same philosophical system. I focus on the macro mechanism of

the amount of memory it occupies on real physical memory.When the program is written, if there is no parallel programming method, then the process can only be run on a CPU, if the use of parallel, then the program will execute a number of execution flow, each execution flow can be executed on a CPU, so that can significantly improve system performance, This implementation flow concept we can simply understand it as a thread , in MySQL, for example, MySQL is high-performance because of multiple

resources. They have NVRAM for the cached read and write. When the cache is used for RAID rebuilds, it uses the backed up battery power to keep the cache, even if a power failure occurs. For large-scale use is very expensive investment.Important RAID Concepts Checksum method to regenerate the lost content from the information saved by the checksum in the RAID rebuild. RAID 5,raid 6 is based on checksums. Striped is to randomly store the slice

of the call to the Move method, we passed only the DX and dy two parameters, and do not need to pass the self parameter (because self is for internal use only).My summer can run.sub-classThe category itself can be further subdivided into sub-classesFor example, birds can be further divided into chickens, geese, oriole.In OOP, we express these concepts through inheritance (inheritance) .class Chicken (Bird): = ' walk ' = Trueclass Oriole (Bird

Beauty would fade but Love would stay. ECMA-262 describes all the basic concepts of JavaScript through ECMAScript. Before we get to the basics of how JavaScript works, let's review the history of ECMAScript: 1) What does JavaScript have to do with ECMAScript? JavaScript has much more meaning than ECMAScript, and a complete JavaScript implementation consists of a three-part ECMAScript, DOM, and BOM, where ECMAScript is the core of JavaScript

AOP, or aspect-oriented programming, is a complement and refinement of OOP, where the duplication of code in OOP is detrimental to the reuse of individual modules, and AOP technology uses a technique called "crosscutting" that splits the inside of encapsulated objects and encapsulates common behaviors that affect multiple classes into a reusable module , and name it "Aspect", that is, facets. The so-called "cut-off", simply said that is unrelated to the business, but for the business module call

Introducedwhen your organization decides to upgrade to Exchange Server To experience some new features, such as integrated e-mail archiving, discovery capabilities, and highly available features. Whether you like it or not, you should be aware that PowerShell is already part of the Exchange Server Administration tool, and you need to learn some basic scripting knowledge to build some script management Exchange Server. This book is an introduction to this. In this chapter, Some of the core

Linux disk partition editing This entry is missingInformation Bar, supplement the relevant content to make the entry more complete, but also can quickly upgrade, quickly to edit it! Linux disk partitioning to master the Linux partition, first understand the physical structure of the hard disk. In order to understand the physical structure of the hard disk, the hard disk can be regarded as a circle, it is made of hard metal materials coated with magnetic media, different capacity of the disk size

You don't have to get other people's consent on everything. As a professional web developer, you are an advocate of your visitors ' interests and needs, and you must stick to your understanding of a good user experience to ensure that your visitors may still find their way under a complex web site architecture. This means that when discussing with users and colleagues, you must be able to stick to your position and communicate your ideas effectively. In fact, your job is to compromise the idea o

Today's small series to share the daily collection and collation of the basic concepts of database, for everyone in the future work is very helpful. 1, Super Key, candidate key, primary key, foreign key Super key: The set of attributes in a relationship that uniquely identifies a tuple is called a hyperlink to a relational pattern. A property can be used as a super key, and multiple attributes can be grouped together as a super key. The Super key co

, the whole process is called context switching, which is not only time consuming, but also invalidates many caches in the CPU, which is a cost.Of course, these costs are relatively relative, and these costs are acceptable if the threads actually do a lot of things, but if you just perform the counter++ in the example in this section, that would be too expensive.In addition, if the tasks performed are CPU intensive, that is, the CPU is mostly consumed, it is unnecessary to create a thread that e

program.What does that mean?System.out.println (strvalue);When you have code that's like accessing strvalue,We're going to turn Java into compile class,decompile.Will discover that it becomes the following codeSystem.out.println ("Ken");Okay, well, where the hell is the risk?Of course, if you could use some good ides today,Should not encounter such risks,In eclipse, for example, if you save or execute, Eclipse will help you with the compile!.(If there is a tick to build automatically)But if you

= Bird ()print ' After Move ', Summer.move (5,8)We redefined the bird category. The bird adds a method attribute, which is the Move method.There is a self in its argument, which is to make it easier for us to refer to the object itself. Method with a parameter must be self whether or not it is used, about selfThe content will be shown in the next lectureFor the other two parameters, dx dy represents the distance traveled in X, y two directions. The Move method eventually returns the position th

Layout:defaultTitle:java layering concept (RPM)Category: [Technology, Java, code Learning]Comments:true---Java Layering Concepts (RPM)For the concept of layering, seems to be a simple three layers, more, it is a bit difficult to distinguish, so the collection of this.Ervice is the business layer action layer that is used as the controller DAO (data access Object) to access 1. What is the function of the action layer, service layer, modle layer and DAO

corresponding servlet, because the JSP compiler is transparent to the programmer, so when the programmer modifies the JSP, the container will check if the JSP has been updated in the conversion.The compiled servlet will typically change the xx.jsp name to the xx_jsp servlet, which implements Org.apache.jasper.runtime.HttpJspBase. The code for the JSP transformation is primarily in the Void_jspservice method of the corresponding servlet, similar to the service method of the native servlet.　　The