java certification test questions

Java Testing System First of all, I would like to thank you for your support, from the Java Test Question System 4-1 to the morning 4th. Reads: 51525 Answer: 21879 Incorrect answer: 18037 Average precision: 54.7% According to the feedback function provided by the system, the answer is incorrect mainly for the following reasons: 1. I have read the wrong q

Note: This article is reproduced: https://i.cnblogs.com/EditPosts.aspx?opt=1For questions, check out several other blogs:Java Basics: http://blog.csdn.net/u014206526/article/details/52251355JVM article: http://blog.csdn.net/u014206526/article/details/52251789Design Pattern article: http://blog.csdn.net/u014206526/article/details/52251924Web article: http://blog.csdn.net/u014206526/article/details/52251948MySQL article: http://blog.csdn.net/u014206526/

java face test-persistence layer 10 91, what is ORM.Object-Relational mapping (object-relational Mapping, or ORM) is a technique to solve the problem of mismatch between the object-oriented model of program and database; To put it simply, ORM is to automatically persist objects in a program to relational databases or to convert rows from relational database tables into

key and index relationshipCreates a primary key, and it automatically creates a unique index with the same name associated with it. When you delete a primary key, both the primary KEY constraint and the corresponding unique index are deleted.A PRIMARY key constraint exists, there must be a unique index corresponding to it, and a unique index does not necessarily correspond to a primary key constraint.******************************************************************************************20. T

Java face test-frame nine 81, what are the benefits of using the spring framework? Lightweight: Spring is lightweight, the basic version is about 2MB. Control reversal: Spring enables loose coupling through control inversion, and objects give them dependencies, rather than creating or locating dependent objects. Aspect-oriented programming (AOP): Spring supports facet-oriented programming and separates app

Write in front: the test and resolution of Netty concurrency problem is completely beyond my expectations, more and more things to say. So this medium, that is to say, there will be the next article. As for the discovery of the problem point, Onecoder is also trying to verify.Continue the concurrency problem. In the Java NIO Framework Netty Tutorial (11) Concurrent access

A total of 40 choice questions, 2.5 points per question. Multiple-choice mistakes are all wrong, the full score.Single topic:1. Which of the following statements is wrong? BA. int i=10;B. float f=1.1;C. Double d=34.4;D. Byte b=127;2. Which of the following is not a keyword in Java? CA. PublicB. TrueC. MainD. Class3. Which of the following statements does not produce a compilation error? CA. Float a = 2.0;B.

------Java Training, Android training, iOS training,. NET training, look forward to communicating with you! As the first Dark Horse technical blog It is necessary to explain the background. The personal understanding of the blog is to be used in communication, in his study, in the exchange of learning to grow together. Let's get down to the chase. This article is mainly to introduce the black horse in the introduction of testing some of the problem

expected to not be reached normally. Assertions can be used to validate parameters that are passed to a private method. However, assertions should not be used to validate arguments passed to public methods because, regardless of whether the assertion is enabled, the public method must check its Parameters. However, you can test the post condition with assertions in a public method or in a Non-public method. In addition, assertions should not change

Here are 10 classic Java interview questions, as well as a list of answers for everyone. This is a Java developer interview often easy to meet the problem, I believe you understand and grasp will certainly improve. Let's take a look at it.How does the 1.Java hashmap work?HashMap is a key value for the data structure, e

have been written by another thread, 2) write the next variable that might be read by another thread(2) Consistency synchronization : When you modify multiple related values, you want the other threads to see this set of changes atomically-either see all the changes or see nothing.This applies to related data items, such as the location and rate of particles, and metadata items such as the data values contained in the linked list and the chain of data items in the lists themselves.In some cases

One of the questions in the Java written test face1, Struts1 in Actionform and action belongs to the MVC layer, why?Answer: Actionform and action belong to the MVC model layer, action is used to process business logic, actionform save user form data to facilitate passing between different pages. The model layer in MVC is the business Logic layer, which is used to

print output? Let's take a look at what this program does: Initialization of a Bitset object Two threads running in parallel, setting the field value to true for the first and second digits respectively We tried to get these two threads running at the same time. Reads the value of the Bitset object, and then outputs the result. Next, we need to construct some test cases to check these behaviors. Obviously, one of them can only r

Java Second Test summary 1. Related knowledge points summarizing Java test questions loops and recursive knowledge pointscomplementary points of knowledge : For Loop statement: for (expression 1; expression 2; expression 3) expression one is responsible for the init

Build pho development environment and frame diagram HanshunpingThe first chapter:No1 about the management of files and foldersThe resulting text document is in the form of detailed information, showing file modification time and file size, facilitates file viewing and management, and is also a professional literacy requirement for an IT person to work efficiently. As shown in the following:In order to facilitate the timely and correct Java files to fi

Java face test-database article 11 As a Java back-end developer, database knowledge is essential to the database to master the familiarity of the investigation is the person has a solid basic skills. Especially for novice developers, the interview may not ask about framework-related knowledge, but will not go to the database knowledge, here to collect some commo

authentication method. But when it comes to Java connectivity, it has an impact.I'm the rookie, just at the beginning, I chose Windows authentication, but it was displayed when I connected."The login is from an untrusted domain and cannot be used with Windows Authentication"I Baidu a bit, find a lot, online have the same question questions, some people replied that "verification method mixed"Read this, the

record some of the good pen questions you've encountered 1, The following Java program outputs the result to ___. int i=0; Integer j = new Integer (0); System.out.println (i==j); System.out.println (J.equals (i)); Answer: TRUE parsing:The subject is an automatic disassembly box of the exam (automatic unboxing of the JDK required 1.5)1, the basic type and basic type of package for the "= =" operator compa

Java connection to various pitfalls of sqlserver (test by cainiao) and javasqlserver As a cainiao, when I first started to use java to connect to sqlserver, it took a short time, I think it is necessary to share my experience with you. (Because I step on most pitfalls) First pitfall: load the driver. Java requires a d

First, written questions:1. Describe the difference between class and object, and the function of Java virtual function.A class is an abstraction of an object that is a concrete instance of a class.Classes are abstract, do not occupy memory, and objects are specific and occupy memory space.Java does not have the concept of virtual functions, the normal function is equivalent to the virtual function in C + +