java interview questions for 7 years experience

;. 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 }

COSCO Java interview question zzz COSCO Java interview questions Java training materialsI. Java language1. Three basic features of object-oriented2. Concepts and differences between met

). 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

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

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

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

) 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

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

space operation is the fastest but also very small, usually a large number of objects are placed in the heap space, the entire memory, including the hard disk of virtual memory can be used as heap space.String str = new string ("Hello");In the above statement, STR is placed on the stack, the string object created with new is placed on the heap, and the literal "hello" is placed in the static storage area.Supplement: A technique called escape analysis is used in newer versions of

In the company as a technical interviewer for a few years, from graduating students to work more than 10 years of candidates have met. Let me start by expressing my own views on the interview:1. Written test, interview to evaluate a person is certainly not accurate, understand a person the most accurate way is "road di

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

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

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

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

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