java interview questions for testers

ImportNew Note: This article is one of the Java interview series compiled by ImportNew. You can view all the Java interview series from here. The common Interview Questions introduced in this article are about the overloading meth

picture suffix 2, how to suffix is tampered with, then each file has a magic digital file upload-magic number5, the principle and implementation of Message Queuing Answer: 1, Message Queuing Principle 2, comprehensible message queue ActiveMQVi. Database Aspects1. The MySQL query field area is not case-sensitive?Answer: Do not differentiate, even if the value is not differentiated (I asked at the time, the area of the application of the size of the meaning of what, the interviewer did not say)2,

. Briefly describe the meaning of the viewThe meaning of a view lies in two ways:1) simplify complex queries. If you need to perform a complex query frequently, you can build a view based on this complex query, and then query this view.2) Restrict data access. A view is essentially a SELECT statement, so when you access the view, you can only access the columns that are involved in the corresponding SELECT statement, and the other columns in the Base table act as security and secrecy.11. What ar

a daily sentence: Life is full of expectations, the dream of connecting the future! Java fresh or self-taught beginner's written interview topic summary, I hope that everyone has help, the topic from their own learning summary and teacher explanation, network resources, books and materials. Knock out everyone to see, every time to update the topic, I hope you can find a good job.Part I: The basic partThe un

;. 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

Java Algorithm interview questions: Separate them with carriage return or space in the answer file ., Package com. swift; import java. io. bufferedReader; import java. io. bufferedWriter; import java. io. fileInputStream; import

threads are not able to modify objects in the collection that is being traversed by iterator. At the same time, iterator allows the caller to delete elements from the underlying collection, which is not possible for enumeration.What is the difference between 17.HashSet and TreeSet?HashSet is implemented by a hash table, so its elements are unordered. The time complexity of the add (), remove (), contains () method is O (1).On the other hand, TreeSet is implemented by a tree-shaped structure in

. } } 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 }

). 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

Java, which meansThird-party applications developed by the SDK must use the Java language. However, this is not equivalent to "third-party applications can onlyUse Java ". At the first release of the Android SDK, Google claimed that its virtual machine Dalvik supported JNI programming.Method, that is, third-party applications can call their own C dynamic library

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

) Select the correct collection type as needed. For example, if you specify a size, we will choose an array instead of a ArrayList. If we want to traverse a map in order of insertion, we need to use TreeMap. If we don't want to repeat, we should use set.(2) Some collection classes allow you to specify the initial capacity, so if we can estimate the number of stored elements, we could use it to avoid re-hashing or resizing.(3) programming based on interfaces, rather than implementation-based prog

TreeMap. If we don't want to repeat, we should use set.(2) Some collection classes allow you to specify the initial capacity, so if we can estimate the number of stored elements, we could use it to avoid re-hashing or resizing.(3) programming based on interfaces, rather than implementation-based programming, allows us to easily change the implementation later.(4) Always use type-safe generics to avoid classcastexception at run time.(5) Using the immutable classes provided by the JDK as key to t

corresponding action, while the user's data to fill the corresponding actionform, and then the Actionform is distributed to action for processing.3.Action automatically calls the Excute method, in which the action takes the user-filled data from the Actionform and invokes the model (JavaBean) for processing, and then displays the results of the processing in a different view (JSP page)struts-config.xml:struts 's configuration file .It says that each user's request is handled and forwarded throu

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

Huawei's Java interview questions Question No: 1 1. Public class test { Public static void changestr (string Str ){ STR = "welcome "; } Public static void main (string [] ARGs ){ String STR = "1234 "; Changestr (STR ); System. Out. println (STR ); } } Please write the output result: Question No: 2 1. Public class test { 2. Static Boolean Foo (char c ){ 3. syst

Sword refers to Java Implementation of offer programming questions-the integer power of the value of interview question 11, and sword refers to offer Question: Implement the double power (double base, int exponent) function to calculate the power of base's exponent. Do not use library functions, and do not need to consider large numbers. Solution: the most common

Sword refers to the Java Implementation of offer programming questions -- interview question 6 re-constructs a binary tree, and sword refers to offer Question: Enter the result of the forward and middle traversal of a binary tree. Create a New Binary Tree. Assume that the input results do not contain repeated numbers.For example, if the input preorder traversal s