Java

There are only two types of Java: underlying type, reference type8 Basic type: byte short int long float double char Boolean, where byte type takes value range " -2^7~2^7-1", Short typeThe value range is " -2^15~2^15-1", and the int type takes the

Windows:1. Install the JDK, note that it is not the JRE2, computer → properties → advanced system settings → advanced → environment variables, select the following system environment variable3.System variables → new java_home variable.Variable value

Background thread, daemon thread (Daemon thread)The so-called background thread means that this thread is not part of the program, so when all non-background threads end, the program terminates and kills all the background threads in the process.

Java.util.concurrent Package Detailed analysisJava.util.concurrent contains many concurrent building blocks that are thread-safe, well-tested, and high-performance. To be blunt, the purpose of creating java.util.concurrent is to implement the

Note reference: 1.service.xml Configuring annotation ModeXML version= "1.0" encoding= "UTF-8"?>Beansxmlns= "Http://www.springframework.org/schema/beans"Xmlns:xsi= "Http://www.w3.org/2001/XMLSchema-instance"Xmlns:context=

"Java Web from Getting started to mastering"--This is the teacher gave us, I found here the things are very comprehensive, but also very detailed, worthy of the teacher gave us. I want to do some exercises in this week's work according to the

Why is it that Java is platform-independent? Java implementation Platform Independent mechanism is the "intermediate code" and "JVM" interpretation of the process of execution is divided into 3 steps: Code loading (load), code check (check), Code

Be sure to configure the set method for the property at the time of input, because the setting is not injected.1.listUserservice.javaPrivate ArrayList arr; Public ArrayList Getarr () { return arr;} Public void Setarr (ArrayList arr) {

Just when it comes to the reflection mechanism, remember that there is a saying that all classes are instances of class, and this class is Java.lang.Class.     At that time very do not understand, I can understand Student student=new Student (),

In the first article, we introduced the two core objects in NiO: Buffers and channels, when it comes to buffers, we say that the buffer object is essentially an array, but it is actually a special array, and the buffer object has built-in mechanisms

In the previous article, we introduced the tracking mechanism of the state change inside the buffer, but for the buffer in NiO, there are a lot of content value learning, such as the partition of buffer and data sharing, read-only buffer and so on.

Given an array of integers, return indices of the both numbers such that they add-to a specific target.You may assume this each input would has exactly one solution.Example:Given nums = [2, 7, one, 2], target = 9,because nums[0] + nums[1] = + 7 =

Some of the details about the buffer are described in the previous article, and it is now finally possible to get into the most interesting parts of NiO that are non-blocking I/O. Typically, when synchronizing I/O operations, if the data is read,

public static String getipaddr (HttpServletRequest request) {String IP = request.getheader ("X-forwarded-for");if (IP = = NULL | | ip.length () = = 0 | | "Unknown". Equalsignorecase (IP)) {ip = Request.getheader ("Proxy-client-ip");}if (IP = = NULL |

Original: http://www.cnblogs.com/skywang12345/p/3479083.htmlDescription of the difference between start () and run ()Start (): Its role is to start a new thread, and the new thread executes the corresponding run () method. Start () cannot be called

Install JDK and environment variable configuration in Ubuntu, and use ubuntujdk environment variable. 1. getconf LONG_BIT: view the number of system digits and download the corresponding jdk.My system is 32-bit, so the downloaded jdk is:

Spring transaction nesting ReferencePROPAGATION_REQUIRED -- supports the current transaction. If no transaction exists, a new transaction is created. This is the most common choice.PROPAGATION_SUPPORTS -- supports the current transaction. If no

Spring aop intercepts business methods to implement permission control and aop permission Control Difficulty: The aop class is a common java class and the session cannot be injected. So how can we obtain user-related information in a stateful

Java calculates the intersection of two arrays (sets), the Union set, the difference set, and the java Array For two Arrays Arr1 = [1, 3, 4, 5, 8, 9] Arr2 = [2, 3, 7, 8, 9] Returns the intersection and union. Test. java 1 import java.util.ArrayList;

Java multithreading and static methods, java multithreading static Java does not have the Foundation to develop Android applications and finds that it does not have sufficient understanding of static methods. The following problems