Java training materials
First, Java language
1, three basic characteristics of object-oriented
2, the concept and difference of method overload and method rewriting
Overriding Overriding is a manifestation of polymorphism between parent class and subclasses, and overloading overloading is a manifestation in a class. If a method is defined in the subclass with the same name and parameters as its parent class, we say that this method is overriddled. When the subject of subclass uses this method, the definition of the subclass will be called. For it, the definition in the parent class is like "shielded". If a plurality of the same names are defined in a class, they or have different parameters or different parameter types, called overloading. The way OVERLOADED is to change the type of return value.
3, interface and internal class, the characteristics of abstract classes
4. Basic class read and write
* 5, serialization precautions and how to implement serialization
6, the basic concept of thread, the basic state of the thread and the relationship between state
7, the synchronization of threads, how to implement the synchronization of threads
8, several common data structures and internal implementation principles.
9, Socket Communication (TCP, UDP Differences, Java Implementation)
* 10, Java event commission mechanism and garbage collection mechanism
11. Basic steps for JDBC calls the database
* 12, analyze the ways and differences of XML files
13. Definition of four basic permissions of Java
14, Java Internationalization
Second, JSP
1, at least you can say that 7 implied objects and their differences
Request Request represents the HTTPServletRequest object. It contains information about the browser request and provides a number of methods for obtaining cookie, header, and session data.
Response response represents the HTTPServletResponse object and provides several methods for setting the response to the browser (such as cookies, header information, etc.)
Out out object is an instance of javax.jsp.jspwriter, and provides several ways to make you use to return output results to your browser.
PageContext PageContext represents a javax.servlet.jsp.pageContext object. It is an API for convenient access to various range spaces, servlet-related objects, and wraps a generic Servlet related feature.
Session session represents a request Javax.Servlet.http.httpsession object. SESSION can store the status information of the user
Application Applicat Indicates a Javax.Servle.ServletContext object. This helps find information about the Servlet engine and the servlet environment
Config config represents a javax.servlet.ServletConfig object. This object is used to access the initialization parameters of the servlet instance.
Page Page Represents a servlet instance from this page
* 2, the difference between Forward and Redirect
3, JSP common instructions
INCLUDE contains a static file and resolves the JSP statement
Page page properties
Taglib tag library
JSP: Forward is defined to an HTML file, JSP file, a block
JSP: Include full of a static or dynamic file, parameter Page Flush
JSP: Plugin executes an applet or bean
JSP: SetProperty Set the attribute value in the bean
JSP: UseBean creates a bean instance and specifies his name and scope
Third, servlet
1, call doget () and dopost () under what circumstances?
2, the intervilet's init () method and service () method difference
3, the life cycle of servlet
4, how to real real servlet single-thread mode
5, servlet configuration
6, four session tracking technology
Four, EJB
* 1, the service provided by EJB container
It mainly provides services such as declaration cycle management, code generation, continuous management, security, transaction management, lock and distribution management.
2, EJB role and three objects
EJB roles mainly include Bean Developers Application Assembarer Deployer System Administrator EJB Container Provider EJB Server Provider
Three objects are Remote (local) interface, home (localhome) interface, Bean class
3, several types of EJB
Session Bean, entity (Entity) bean message driver (Message Driven) bean
Session bean can be divided into stateful and stateless
Entity Beans can be divided into two kinds of sustainability (BMP) and container management of bean management (CMP)
4, life cycle of the bean instance
For Stateless Session Bean, Entity Bean, Message Driven Bean typically exists in cache management, which typically contains Cache management, set up the context, create EJB Object (create), business method call, remove, etc. Procedure, for the bean in which the buffer is managed, the instance is not removed from memory, but the buffer pool scheduling mechanism continues to reuse the instance, and the bean in which Cache Management is used, the BEAN is maintained by activating and deactivating the mechanism. Limit the number of instances in memory.
5, activation mechanism
Take the Statefull Session Bean as an example: The Cache size determines the number of bean instances that can exist in memory, according to the MRU or NRU algorithm, instance migrate between activation and deactivation, activation mechanism is when the client calls an EJB When an instance business method, if the corresponding EJB Object discovers that it does not bind the corresponding bean instance, the reactive bean storage (by serializing mechanism storage instance) is replied (activated) this instance. The corresponding EJBACTIVE and EJBPASSIVATE methods are called before the state change.
6, the main role of the Remote interface and HOME interface
The REMOTE interface defines a business method for the EJB client calling business method.
The HOME interface is an EJB factory for creating and removing a lookup EJB instance
7. Several basic steps for the customer service end call EJB object
First, set the JNDI service factory and JNDI service address system properties
Second, find home interface
Third, call the CREATE method from the home interface to create a Remote interface
Fourth, call its business method through the Remote interface
V. Database
1. Writing of the stored procedure
2. Basic SQL statement
Sixth, WebLogic
1. How to specify the size of the memory to WebLogic?
In the Script of WebLogic (bitservername in the Domian corresponding server directory), add SET MEM_ARGS = -XMS32M -XMX200M, adjust the minimum memory to 32M, maximum 200M
2, how to set the hot start mode (development mode) of WebLogic and product release mode?
The startup mode of the corresponding server can be modified in the management console is one of the development or product modes. Or modify the service startup file or Comufact of the Commenv file, add set production_mode = true.
3, do you need to enter your username and password when starting?
Modify the service launch file, add WLS_USER and WLS_PW items. You can also add an encrypted username and password in the boot.properties file. 4. After the WebLogic Management Table is configured to configure a application domain (or a website, Domain), and What file is actually saved?
Save in the config.xml file of this Domain, it is the core profile of the server.
5. Talk about the default directory structure of a Domain in WebLogic? For example, put a simple helloWorld.jsp into the why directory, but you can be http: // host on the browser: port number // HelloWord .jsp You can see the result of the running?
Domain Directory / Server Directory / Applications, place the application directory in this directory will be available as an application access. If it is a web application, the application directory needs to meet the web application directory requirements, the JSP file can be placed directly in the application directory, Javabean needs to be put In the CLASSES directory for the application directory, the default application that sets the server will be able to implement the application name on your browser.
6, how do I view EJBs already released in WebLogic?
You can use the management console, you can view all published EJBs in its deployment
7, how to make SSL configurations in WebLogic and the client's authentication configuration or talk about J2EE (standard) for SSL configuration
Using DemoIdentity.jks and Demotrust.jks KeyStore in the default installation, you need to configure the server to use Enable SSL, configure its port, you need to get private key and digital certificate from CA in product mode, create Identity and Trust KeyStore, load get Keys and digital certificates. You can configure this SSL connection to one-way or two-way.
8, which configuration files need to be involved in the WEBLOGIC
The configuration files involved in different types of EJBs have different configuration files including EJB-jar.xml, weblogic-ejb-jar.xmlcmp entity beans generally need WebLogic-Cmp-Rdbms-jar.xml
9, EJB needs to implement its business interface or home interface, please briefly describe the reasons.
The remote interface and home interface do not need to be directly implemented, and their implementation code is generated by the server, and the implementation class in the program run is used as an instance of the corresponding interface type.
10. Talk about the difference between Persistent and Non-Persisten when developing message beans in WebLogic
The MDB of the Persistent method ensures the reliability of the message delivery, that is, if the EJB container has problems, the JMS server will send the message when this MDB can be used, and the Non-Persistent method will be discarded.
11. Talk about several common modes in J2EE you are familiar with or have heard? And some views on design patterns
Session Facade Pattern: Accessing EntityBean using sessionbean
Message Facade Pattern: Realization asynchronous call
EJB Command Pattern: Use Command JavaBeans to replace sessionBean to achieve lightweight access
Data Transfer Object Factory: Simplify EntityBean Data Provision for DTO Factory
Generic Attribute Access: Simplify EntityBean Data Provision for EntityBeaN
Business Interface: Realize the same interface to specify business logic through remote (local) interface and bean classes
