13 Specifications for Java EE

Java EE Presumably everyone is not strange, it seems that now more popular to call it Java EE, no matter how the name changed, the core and the idea is unchanged. Learn the Java EE first to understand its specifications, let's look at its 13 specifications.

1,JDBC (Java Database Connectivity)

The Java API for executing SQL statements, which provides unified access to a variety of relational databases, consists of a set of classes and interfaces written in the Java language.

Personal understanding: Like Microsoft's ODBC, it should be said that the combination of ODBC and ADO. Can be understood as object-oriented ODBC, and there is no doubt that object-oriented interfaces are easier for Java programmers to understand. ODBC puts simple functions together with advanced features, which are relatively difficult to learn, and JDBC tries to keep simple functionality easy, while also using advanced features when needed. JDBC is optimized for Java's style and benefits, making it even more handy when used.

2,jndi (Java Name and Directory Interface)

API for accessing naming and directory services in Java applications. The naming service links names to objects so that we can access them by name.

Personal understanding: Jndi is intended for access to the directory infrastructure used in advanced Web application development. This directory is actually a special database that provides quick access to stored data, unlike traditional directory service access, which must provide different API interfaces to access different directory services (such as ldap,nis,ads, etc.), which unify the interfaces of different types of directory access. Both Jdni and JDBC are built on the abstraction layer.

3,EJB (Enterprise Javabean)

EJB is the Sun's server-side component model, and the design goal and core application is to deploy distributed applications. EJB is the core code of Java, namely the session bean, the entity bean and the message-driven bean (Messagedriven bean).

Personal understanding: EJB is a big contributor to the extensive use of Java EE by programmers and is the core of the Java EE. EJB provides a framework for developing and implementing distributed business logic, which greatly simplifies the development of high-complexity, easy-to-scale enterprise applications. There is no further discussion about three specific beans in the next article.

4,rmi (Remote Method Invoke)

RMI refers to a remote method call. It is a mechanism that enables an object on one Java virtual machine to invoke a method on an object in another Java virtual machine. Any object that can be called with this method must implement the remote interface.

Personal understanding: RMI is a very important underlying technology, is the basis of the distribution, just mentioned EJB is based on the RMI. RMI is simpler than a heavyweight component such as a Web service, and is better suited for use in small-scale applications.

5,java Idl/corba

Java Interface Definition Language/Common Object Request Agent architecture

Personal understanding: With the support of Java IDL, developers can integrate Java with CORBA. They can create Java objects and make them expandable in the CORBA orb, or they can create Java classes and serve as clients for CORBA objects that are expanded with other orbs. The latter approach provides another way through which Java can be used to integrate your new application with the old system.

6,jsp (Java Server Pages)

A JSP is a JSP file (*.jsp) that is inserted into a Java program segment (scriptlet) and JSP tag (tag) in a traditional Web page HTML file (*.htm,*.html). Web applications developed with JSP are cross-platform.

Personal understanding: JSP and ASP very much like, ASP is to add the. NET code on the basis of HTML, and JSP is based on the HTML to add Java code, they are dynamic web pages, and the biggest advantage of JSP is the cross-platform, not only can run on the Windows platform, but also on Linux or other operating systems.

7,servlet

A servlet is a server-side Java application that has platform-and protocol-independent features that can generate dynamic Web pages. It serves as the middle tier of a customer request (a Web browser or other HTTP client program) and a server response (a database or application on an HTTP server). A servlet is a Java application located on the server side of a Web server, unlike a traditional Java application launched from the command line, which is loaded by a Web server that must contain a Java virtual machine that supports Servlets.

Personal Understanding: Servlets provides the same functionality as most jsps, and it uses a somewhat different approach. Most of the JSP is HTML code, in which there is only a small amount of Java code, and Servlets is the opposite, it is written entirely in Java, and can produce HTML code. JSP does not add any functionality that is inherently not possible with the servlet. However, it is more convenient to write static HTML in the JSP without having to use the PRINTLN statement to output each line of HTML code. More importantly, with the separation of content and appearance, tasks of different natures in page authoring can easily be separated: for example, HTML design by the page designer, while leaving room for the servlet programmer to insert dynamic content. Servlets are similar to Microsoft's general handlers.

8,xml (extensible Markup Language)

Used to tag electronic files with a structured markup language that can be used to tag data, define data types, and is a source language that allows users to define their own markup language. XML is a subset of standard Generalized Markup Language (SGML) and is ideal for Web transport. XML provides a unified approach to describing and exchanging structured data that is independent of the application or vendor.

Personal understanding: XML is a language used to define other markup languages. It can be used as a data sharing between businesses. The development of XML and Java are independent of each other. However, it has the same goal as Java and is cross-platform. By combining Java with XML, we can get a completely platform-agnostic solution.

9,JMS (Java Message Service)

The JMS-Java Message Service Application interface is an API for message-oriented middleware (MOM) in the Java platform for sending messages between two applications, or distributed systems, for asynchronous communication. The Java Messaging Service is a platform-agnostic API, and the vast majority of MOM providers support JMS.

Personal understanding: JMS is an Application interface (API) for communicating with each other for message-oriented middleware. It supports both a point-to-point domain and a publish/subscribe (publish/subscribe)-type domain, and provides support for the following types of messages: Approved messaging, transactional message delivery, consistent messaging, and persistent subscriber support. JMS also provides another way to integrate your application with the old backend system.

10,jta (Java transaction Architecture)

Java Transaction API. Allows applications to perform distributed transactions-access and update data on two or more network computer resources. The JTA support of the JDBC driver greatly enhances the data access capability.

Personal understanding: JTA defines a standard API that the application can use to access the transaction monitor. JTA transactions are more powerful than JDBC transactions. A JTA transaction can have multiple participants, while a JDBC transaction is limited to a single database connection.

11,jts (Java transaction Service API)

JTS is a basic implementation of CORBA OTS transaction Monitor. JTS Specifies a transaction manager implementation (Transaction Manager) that supports the Java Transaction API (JTA) specification at a high level, and implements the Java mapping of the OMG OTS specification on a low level. A JTS transaction manager provides transaction services for application servers, resource managers, standalone applications, and communication Explorer.

12,javamail

JavaMail is an API used to access the mail server. The JavaMail API provides a set of abstract classes to model a messaging system. Supports SMTP and IMAP servers.

13,JAF (JavaBean Activation FrameWork)

JAF is a dedicated data processing framework that encapsulates data and provides an interface for applications to access and manipulate data. The primary role of JAF is to let Java applications know how to view, edit, and print a data source.
All versions of the Mail API require the JavaBeans Activation Framework to support the input of arbitrary blocks and the corresponding processing. Features don't seem to be much, but this basic MIME-type support is now available in many browsers and mail tools. The Activation.jar file is the framework jar package for JAF.

Finally finished, I have to say that writing this kind of more abstract things really time-consuming laborious and cost brain cells Ah! At present, the understanding of the Java EE is very superficial, but also needs in the future study and practice in-depth, I hope we have a lot of guidance.

13 Specifications for Java EE