81. 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.
82. 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.
83. After the application domain (or a website, Domain) is configured to configure the relevant information such as a application domain (or a website, domain) in the WebLogic Management State, which is actually saved in what file?
Save in the config.xml file of this Domain, it is the core profile of the server.
84, talk about a Domain default directory structure in WebLogic? For example, put a simple helloworld.jsp into the point of the directory, but you can be http: // host on the browser: port number // HelloWord .jsp You can see the result of running? Another example this is to write JavaBean what to do?
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.
85. What 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
86. How to make an SSL configuration in WebLogic to configure 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.
87. How to view EJBs already released in WebLogic?
You can use the management console, you can view all published EJBs in its deployment
88, what is CORBA? What is the use?
The CORBA standard is a common object request agency structure, which is standardized by object management organization (Object Management Group, abbreviated as OMG). Its composition is the interface definition language (IDL), language binding (binding: also translated into a cable) and an agreement to interoperate interoperability. Its purpose is to use different programming languages to run in different processes, develop in different operating systems.
89. Talk about several common modes in J2EE you are familiar 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: Simplifies EntityBean Data Provision for EntityBeaN data by AttibuteAccess interface: The same interface specification business logic consistency is implemented by remote (local) interface and Bean class.
The design of the EJB architecture will directly affect the performance, scalability, maintenanceability, components reusability and development efficiency. The more complex the project, the more important the project team, the more important it can reflect the importance of good design.
90, tell 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.
91. What kind of method is generally implemented when the servlet is executed?
Public void init (servletconfig config)
Public servletconfig getServletConfig ()
Public String GetServletInfo ()
Public void service (servletRequest Request, ServletResponse Response)
Public void destroy ()
92, J2EE common design model? Description plant mode.
23 design patterns in Java:
Factory, Builder, Factory Method (factory method mode),
Prototype, Singleton, Facade (facade),
Adapter, Bridge (Bridge mode), Composite (synthesized mode),
Decorator, Flyweight, Proxy (proxy mode),
Command, Interpreter, Visitor (visitor mode),
Iterator (Iterative Sizes), Mediator, MEMENTO (Memo Mode),
Observer (Observer mode), Strategy, Strategy (Policy),
Template Method (Template Mode), Chain of Responsibleity (Responsibility Chain Mode)
Factory mode: Factory mode is a model that is often used. The class implemented according to the factory mode can generate an instance of a class in a set of classes in accordance with the data provided. Usually this set of categories have a public abstract parent class and The same method is achieved, but these methods have different operations for different data. First, you need to define a base class that the subclass of the class implements the method in the base class through a different method. Then need to define a factory class, and the factory class can generate different subclass examples depending on the conditions. When an example of a subclass is obtained, the developer can call the method in the base class without having to consider the instance of which a subclass is returned. 93, 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.
94. What kinds of methods are there? Please list it. Implement a rapid sort with Java.
Sort by: Insert Sort (Direct Insert, Hill Sort), Switching Sort (Bubble Sort, Rapid Sort), Select Sort (Direct Selection Sort, Stack Sort), Multiple Sort, Distribution Sort (Sort, Base Sort )
Quickly sorted pseudo code.
/ / Sort a Quick Sorting Method to A [0: N- 1]
Select an element from a [0: N- 1] as M i D l E, the element is fulfilled
The remaining elements are divided into two LEFTs and R I g h t, so that the elements in L E f T are less than or equal to the fulcrum, and the elements in the RIGHT are greater than equal to the fulcrum
Returning use of fast sorting methods to sort Left
Returning use of rapid sorting methods to sort Right
The result of the result is L E f T M I D D L E R I g H t
95, explain the following noun commonly used in J2EE (or briefly description)
Web container: Provides an environment to the application component (JSP, servlet) that interacts the JSP, Servlet directly more in the container, and does not have to pay attention to other system issues. There is mainly a web server to achieve. For example: Tomcat, WebLogic, WebSphere, etc. The interface provided by the container strictly abides by the Web Application standard in the J2EE specification. We call the Web Server of the above standards called the web container in J2EE.
EJB container: Enterprise Java Bean container. More industry segments. He provides various management functions that run the component EJB. As long as the EJB that satisfies the J2EE specification is placed in this container, it will be managed by the container. And you can obtain system level services through ready-made interfaces. For example, email services, transaction management.
JNDI: (Java Naming & Directory Interface) Java Name Directory Service. The main functionality is: Provide a directory system that allows applications from all over its own index to meet the functionality of fast finding and positioning distributed applications.
JMS: (Java Message Service) Java Message Service. It mainly implements communication between the various applications. Includes point-to-point and broadcast.
JTA: (Java Transaction API) Java Transaction Services. Provide a variety of distributed transaction services. The application only needs to call the interface provided.
JAF: (Java Action Framework) Java Security Authentication Framework. Provide some security control frames. Let developers implement their own personal safety control strategies through a variety of deployment and customization.
RMI / IIOP: (Remote Method Invocation / Internet Object Request a Intermediary Protocol) They are primarily used to serve through remote calls. For example, remotely running a program, which provides stock analysis services, we can implement them directly on your local computer. Of course, this is to communicate between heterogeneous systems through a certain specification. RMI is unique to Java. 96. How does Java language processes an exception handle, keywords: throws, throw, try, catch, finally represents what significance? Can I throw an exception in the TRY block?
Java processes abnormally by object-oriented methods, and classifies a variety of different exceptions and provides a good interface. In Java, each exception is an object, which is an instance of the throwable class or other subclass. When an abnormality occurs, an exception object is thrown, and the object contains abnormal information, and the method of calling this object can be captured and processed. Java's exception handling is achieved by 5 keywords: try, catch, throw, throws and finally. Under normal circumstances, use TRY to perform a program, if an exception occurs, the system will throw an exception, then you can capture (catch) it through its type, or finally by default processor Treatment.
Use TRY to specify a program that prevents all "exceptions". Keeping followed by the Try program, a Catch clause should be included to specify the type of "exception" you want to capture.
The throw statement is used to clearly throw an "exception".
Throws is used to indicate a variety of "exceptions" that may be thrown by a member function.
Finally is executed to ensure that "exception" occurs regardless of the code.
You can write a TRY statement outside in a member function call, write another TRY statement to protect other code inside this member function. Whenever you encounter a try statement, the "exception" frame is placed on the stack until all TRY sentences are completed. If the TRY statement at the next level does not process some "exception", the stack will be expanded until the TRY sentence with this "exception" is encountered.
97, can I include multiple classes (not internal classes) in a ".java" source file? What is the limit?
can. There must be only one class name with the file name.
98, all parts of MVC have those technologies to achieve? How to achieve?
MVC is a short written by Model-View-Controller. "Model" is the application's business logic (implemented by javabean, ejb component), "view" is the application's representation surface (generated by JSP page), "Controller" is a process control (generally a servlet) The application logic, processing procedure, and display logic are achieved by this design model into different components. These components can interact and reuse.
99. How many ways to implement a thread in Java? What is the use of keyword modified synchronization methods? Stop () and SUSPEND () methods do not recommend it?
There are two implementation methods, which are inherited the Thread class and the implementation of the runnable interface.
Synchronization method with synchronized keyword
Oppose the use of STOP () because it is not safe. It will release all locks acquired by the thread, and if the object is in a non-connected state, then other threads can check and modify them in that state. It is difficult to check the real problem. The suspend () method is prone to dead locks. When you call suspend (), the target thread will stop, but still hold the lock before this. At this point, any other thread cannot access the locked resource unless the thread is restored to the thread. For any thread, if they want to resume the target thread, it will cause a deadlock to use any lock resources. So you should not use Suspend (), and you should place a sign in your own Thread class, pointing out that the thread should act or hang. If the flag indicates that the thread should hang, use Wait () to enter the waiting state. If the flag indicates that the thread should be restored, use a Notify () to restart the thread. 100. How many types of streams in Java? JDK provides some abstract classes for each type of stream for inheritance, please say which classes are they?
Byte stream, character stream. Byte streams are inherited in InputStream / OutputStream, and the character stream is inherited in InputStreamWriter. There are many other streams in Java.IO bag, mainly in improving performance and convenience.
