java interview questions multiple choice

Java Exception Common interview question one, Java exception understandingExceptions are mainly handling errors that cannot be caught at compile time. The problem can continue to execute smoothly, without causing the program to terminate, to ensure the robustness of the program.Processing: When an abnormal state is generated, if the current context does not have

. } } 56. Problem: Give an integer variable A, write two pieces of code, the first set of a bit3 is 1, the other bit does not change, how to implement it? /** * @author sanchan * @since 1.0 */ publicclassTest{ publicstaticvoidmain(String[]args){ //给一整型变量a，写两段代码，第一个设置a的bit3 为1，其他bit不变，怎么实现呢？ inta=8; //打印二进制 System.out.println(Integer.toBinaryString(a));//输出 1000 System.out.println(Integer.toBinaryString(a|4));//输出 1100 }

Controller: When the user clicks the Submit button in the Web page, the controller accepts the request and invokes the appropriate model to process the request. The corresponding view is then called according to the result of the processing to display the results of the processing. MVC process: First the controller accepts the user's request, invokes the corresponding model for business processing, and returns the data to the controller. The controller invokes the corresponding view to

Collector deletes an object. 13. Can anonymous inner class (anonymous internal class) be extends (inherited) other classes, or implements (implemented) interface (Interface )? An anonymous internal class is an internal class without a name. It cannot be extends (inherited) other classes, but an internal class can be used as an interface and implemented by another internal class. 14. The difference between static nested class and inner class is that the more you say, the better (the more general

). In the process of populating the handler, depending on your configuration, Spring will do some extra work for you: Httpmessageconveter: Converts the request message (such as Json, XML, and so on) to an object, converting the object to the specified response information. Data Transformation: Data conversion for a request message. such as string conversion to Integer, double, and so on. Data is initialized: Data is formatted for the request message. such as converting a string into a formatt

wrapper type , which means that the wrapper type can be converted directly to the base data type , as shown in the following code:int m=100; Integer im=int N=im; The appeal code directly assigns m to the wrapper object IM, which is automatically boxed and then directly assigns the IM to the basic data type N, which is the automatic unpacking. Although the code on the surface is simple and convenient, however, in essence, the container still uses new to create the object, while unpacking is s

This article includes a variety of tedious Java written/interview questions, some of which are easy to forget and occasionally updated. I also hope that you can leave a message below to post all kinds of tedious test and interview questions you have encountered or seen.J2EE

inherit it. Subclass overwrites the finalize () method to sort system resources or perform other cleanup tasks. The finalize () method is called before the Garbage Collector deletes an object. Second, can anonymous inner class (anonymous internal class) be extends (inherited) other classes, or implements (implemented) interface (Interface )? An anonymous internal class is an internal class without a name. It cannot be extends (inherited) other classes, but an internal class can be used as an in

after the real object is called.Proxy mode,The proxy class and the proxy class implement the same interfaceAn instance of a proxy class in a proxy classBehavioral patterns: Focus on communication between objectsSuch as: Responsibility chain mode, iterator mode, command modeResponsibility chain ModelSimilar interceptors, etc.Command mode:Separates callers from Callee's behaviorInterpreter mode:Each syntax is an interpreter classIterator mode:Change the collection class's view traversal and add a

finalize () method to sort system resources or perform other cleanup tasks. The finalize () method is called before the Garbage Collector deletes an object. Second, can anonymous inner class (anonymous internal class) be extends (inherited) other classes, or implements (implemented) interface (Interface )? An anonymous internal class is an internal class without a name. It cannot be extends (inherited) other classes, but an internal class can be used as an interface and implemented by another i

adapter pattern? Ø database How are you usually optimized, what other tools are used to optimize no, how to use the Ø Now there is a lot of tables to correlate the query SQL, the child table data is very much, then you only from the SQL point of view of the SQL statement optimization, do not need to consider the index, predicate Ø you don't have a Java project, do you? Ø your major is to control the direction, why do the current direction O you have

take out 1 position: Product: 4 The consumer takes out from 0 position: Product: 2 producer put in 0 position: Product: 5 consumer removed from 0 Position: Product: 5 producer put in 0 position: Product: 6 consumer is removed from 0 position: Product: 6 producer put in 0 Location: Product: 7 producer puts 1 position: products £ º The producers are placed in the location of the product: 8 Position: Product Consumer removed from 1 position: Product: 9 consumer removed from 0 positions: Products:

I used to have only one Java interview question topic. Now I have divided into the following topics: Java interview questions are of course the focus, all of which are Java programming and directly related to the design. Intelli

is private, then the subclass cannot be overwritten, which is equivalent to adding a new method to the subclass.19. A house has a chair, a chair with legs and back, what is the relationship between the House and the Chair, and what is the relationship between the Chair and the leg and back?If a house has multiple chairs, which is an aggregation relationship, it is an association, and of course, aggregation is a special kind of association. A chair is

Transferred from: http://icyfenix.iteye.com/blog/715301The background of this post is tonight to see JE on this posting: http://www.iteye.com/topic/715256, the words written on impulse, if you can, can have other interviewers to analyze their interview questions asked, it may be a very meaningful thing. In the company as a technical interviewer for a few years, from graduating students to work more than 10

into the corresponding method to invoke the logical layer of the method to achieve response to the customer.There are no doget, dopost, and so on in the Servlet interface and Genericservlet, these methods are defined in HttpServlet, but all return error information, so, each time we define a servlet, Must implement these methods such as Doget or Dopost.Each custom servlet must implement the Servlet interface, and the Servlet interface defines five methods, of which the more important three meth

solves this problem for us. After the online pool submits the callable task, a future object is returned, using which we can know the status of the callable task and get the result of the execution callable returned. The future provides a get () method so that we can wait for callable to end and get its execution results.What is Futuretask?Futuretask is a fundamental implementation of the future, and we can use it with executors to handle asynchronous tasks. Usually we do not need to use the Fu

First, instance variablesAlso called an object variable, a class member variable, the storage space is allocated when the object is generated from the class, and the instance variables between the objects do not interfere with each other, and the instance variables can be accessed through the object's reference. However, in Java Multi-threading, instance variables are multiple threads that share resources,

Java programmer interview questions (86-115) 86. In Struts 2, how does Action obtain the data that the user inputs from the page, and how does it transmit its own data to the view? A: There are three ways for Action to retrieve data from the page: 1) accept parameters through the Action attribute 2) obtain parameters through the domain model 3) ModelDriven )

rewrite the aof file, the performance impact of this persistence is minimal, but the aof file will continue to grow, aof file over the General Assembly to affect the recovery speed of master restart. Master should not do any persistent work, including memory snapshots and aof log files, in particular, do not enable memory snapshots to persist, if the data is more critical, a slave open aof backup data, the policy is synchronized once per second. Master calls bgrewriteaof rewrite aof file, a