java thread interview questions

, StringBuilder and StringBufferStorestring constant, which cannot be changed once the object is createdStringBuilder and StringBuffer: String variables, objects can be changedExecution speedstringThread SafetyString,stringbuilder is thread insecure, StringBuffer is thread-safe.Scope of applicationString: Applies to a small number of string operationsStringBuilder: For a single

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

"Declaration" Source: Power node Java Institute, reprint Source: Script House (The answer to a small number of questions was slightly altered by me) 1, what is the thread local variable. A thread-local variable is a variable within the thread itself, owned by the

-threaded access to shared resources, due to improper access, usually a thread locked a resource A, but also want to lock resource B, and in another thread, the lock resource B, but also to lock resource A to complete its own operations, two threads want the other's resources, Instead of releasing their own resources, two of threads are waiting for a situation that cannot be performed.Java Network Programmi

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

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

variable, the value of the variable in the object changes.[Java]View PlainCopy "FONT-SIZE:14PX;" >public class Demo { //class variable (static variable) public static int a = 0; //Instance variable private String namestring; } Third, local variablesA parameter in a method or a local block that declares a defined variable or method is called a local variable, and they exist only in the block where they were creat

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

in February. The first day of 1751 in England was March 25, 11 days worse than France.After the United States adopted the Gregorian calendar, it went back hundreds of years, so that the dates originally recorded could be expressed in two calendars (usually to provide two dates for more precise purposes). For example, George Washington's birthday changed from February 1731 11 to February 1732 22.When you read a volatile variable in a thread, you can

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

Dark Horse programmer ---- java-based operators, keyboard input, if switch statements, related Interview Questions, ---- javaswitch ------ Java training, Android training, iOS training, and. Net training. We look forward to communicating with you! ------- 1: Operator (master)(1) Arithmetic Operators A: +,-, *,/, %, ++

are characterized by the inability to define variables, and all methods are abstract methods . abstract classes can have variables and do not enforce the need for abstract methods .Inheritance of class 16 and implementation of interfacesParsing: Class Inheriting the parent class implements the interface with the class, which is essentially the same. is to either extend or rewrite the parent class or interface as a template on this template. In practical programming, programmers often need to in

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

JAVA engineer interview questionsZookeeper I went to a company for an interview today. I felt dizzy with my brains. I didn't make a few algorithm questions. The questions were relatively simple. I should have prepared myself, but the status was not good, after the

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

Request object: This method is the same as using the request. GetParameter, as with the traditional JSP, such as passing parameters "") method Java exception, error, and exception exception classification map 1.Error: All inherited from the error, indicating fatal errors, such as insufficient memory, byte code and so on. Error is a program can not handle errors, such as OutOfMemoryError, Threaddeath and so on. When these exceptions occur, the

Java interview questions: Implementation of stacks and queues During the interview, stacks and queues are often checked in pairs. This article includes the following stack and queue test content: 1) stack Creation 2) create a queue 3) Two stacks implement one queue 4) two queues implement one stack 5) design the stack

Encounter an interview today, how to find a dead loop in a bunch of threads?What if I encounter a spike in online application CPU and what happens to Outofmemery?First, the JVM configuration of the online application to develop a good habit, add a configuration to automatically dump the log when the JVM has an oom-xx:+heapdumponoutofmemoryerror-xx:heapdumppath=/export/log /dump/jvm-oom.logHow do I troubleshoot an online application that consumes CPU r

() is a thread interaction, if a thread makes a waiting () call to a synchronization object x, the thread suspends execution and the object is queued until it wakes up or waits. 13th, does Java have goto? The reserved word in Goto-java is not now used in

1. What is acitsag startup mode? For such a question, I will write an example myself. I will observe it to understand it. Activty supports four startup modes. Launchmode: Standard: each time a new activity window is started (New Operation) Singletop: if it is a target activity at the top of the stack, It will be opened directly. Otherwise, a new activity window (new) will be opened ). Singletask and singleinstance are basically the same. The difference is that if the root activity is set to sing