java j2ee interview questions and answers

;. java.util Package: Java Utility Class Library Java.util package. In this package, Java provides some useful methods and data structures. For example, Java provides a date (Data) class, a calendar class to produce and get dates and times, a random number class that produces random numbers of various types, and a stack (stack), vector, bit set (Bitset), and a ha

. } } 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 }

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 )

Java multithreading interview questions Induction1. What are the implementation methods for multithreading? The following example shows the thread synchronization. (1) Java multithreading has two implementation methods: Inheriting the Thread class and implementing the Runnable interface. Thread implements the Runnable

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

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

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

First, let's list these 32 questions. You can leave me alone and think about what it will do if the interview feels like. First, let's talk about the differences between final, finally, and finalize. Second, can anonymous inner class (anonymous internal class) be extends (inherited) other classes, or implements (implemented) interface (Interface )? Third, the difference between static nested class and inner

Java Algorithm interview questions: Read all names from text files similar to the following, print duplicate names and repeated times, and sort by repeated times; read docx and read doc. Use the poi jar package to provide download, Read all names from text files similar to the following, print duplicate names and repeated times, and sort by repeated times 1, Zhan

More than 100 typical JAVA interview questions and answer analysis (1) This article will discuss various types of interview questions in Java interviews, which allow employers to test candidate's

A few days ago in the Java interview problems encountered, this is only part of the problem, there are many questions in the interview about data structures and algorithms. Here to summarize, hope that the ability of people can try to do, and in the comment area to leave your answer, let everyone learn from each other.

Java Algorithm interview questions: Write a Singleton, javasingleton Package com. swift; public class Singleton {public static void main (String [] args) {/** write a Singleton */ORC_Hungry.getOrc (). fun (); ORC_Lazy.getOrc (). fun () ;}} class ORC_Hungry {// hungry Chinese private static ORC_Hungry orc = new ORC_Hungry (); private ORC_Hungry () {} public stati

longer executed.(2) But in the case of a hash collision, the first two conditions are established, and then the last equals must be used to determine the equality of the objects.A 3.hash collision scene?(1) Generally appears in large data situations(2) The generation method of Hashcode is weak (such as the artificial production hashcode above)Summary: This chapter mainly through the introduction of hash collision once again in-depth understanding of hashmap work principle.This chapter is here,

1. The difference between String and StringBufferThe Java platform provides two classes: string and StringBuffer, which can store and manipulate strings, That is, character data that contains more than one character. This string class provides values that cannot be changed strings and the strings provided by this StringBuffer class are modified when you know that character data is going to change, you can use StringBuffer typically, You can use Stri

Difference between Forward and Redirect in common JAVA interview questions, forwardredirect The user sends an HTTP request to the server, which may be returned to the user after being processed by multiple information resources. Each information resource uses the request forwarding mechanism to forward requests to each other, however, the user does not feel reque

Sword refers to the Java Implementation of offer programming questions-interview question 5 prints the linked list from start to end and offer from end to endTopic Description * sword refers to offer interview question 5: print the linked list from the end to the endEnter the head node of a linked list and print the va

Frontier Dream Workshop 2017-04-18 18:14 Most of the Java interview is divided into written and interview, the following issues are cutting-edge education small series according to the major IT enterprises interview asked the questions sorted out, such as the need for releva

Interview questions-java Design Pattern Example 1, adapter modeInvolves three roles: Target destination interface, Adaptee source role, adapter adapter,adapter The source interface to the target interface, inherits the source interface, and implements the target interface .Many examples of Java I/O operations are:Input

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

. 64. What are the similarities and differences between JSP and Servlet, and what are their relationships? JSP is an extension of Servlet technology. It is essentially a simple Servlet method, with more emphasis on the external expression of the application. After JSP compilation, it is "servlet-like ". The main difference between Servlet and JSP is that the application logic of Servlet is in the Java file and is completely separated from the HTML in