Java

First, session technology introduction 1. What is a session and why is session technology required?Session: From opening a browser to visiting a website, the process of closing this browser is called a session. The HTTP protocol is state.2.

This first knowledge combing blog, I hope I can continue to summarize the knowledge.This is the video you see in the Geek College, the catalogue is as follows, pretty clear. Then I'll remember what I said in the video.Java object-oriented generics:

Points:A generic class is a class with one or more type parametersA generic method is a method with a type parameterYou can require a type parameter to be a subtype of one or more typesA generic type is not to become: when S is a subtype of T is,g

Ref:http://www.studytonight.com/java/reflection-apiReflection APIReflection means ability of a software to analyze itself. In Java, Reflection APIs provides facility to analyze and change runtime behavior of a class, at runtimeFor Example, using

This article is from the "in-depth understanding of Java Virtual Machine," a book, it is very recommended that you look at this book. Other articles in this series:"In- Depth understanding of Java virtual machines" Java memory area model, object

1         Static code blockHere's a way to use static modifiers that are not very common. When we need a class, the constructor of this class is private, and other programs outside this class cannot create objects of this class. So how do you

/*** Copy Object Properties (object type must be the same) * *@paramOrig Resource Object *@paramdest Target Object *@paramClazz Source Object class *@paramignorenull whether NULL is ignored (true: ignored, false: not ignored) *@return */

The MAVEN version I used is the latest version: 3.3.9, but I'm going to execute a simple clean command that will report the following error:Exception in thread "main" java.lang.unsupportedclassversionerror:org/apache/maven/cli/mavencli:unsupported

The Java Container class contains list, ArrayList, vector and map, HashTable, HashMapArrayList and HashMap are asynchronous, vectors and Hashtable are synchronous, so vectors and hashtable are thread-safe, and ArrayList and HashMap are not

Summary of Knowledge points: (see example)Multithreading:Threads are created separately in the programControl Unit, is a program that executes concurrently. The procedure executed in the external order is calledMain Thread。A thread is a

One, Java streaming input/output principle　　Stream is used to read and write data, Java has a class called file, it encapsulates the filename of the files, just an object in memory, the real file is a piece of space on the hard disk, in this file

Click to enter _ more _java thousand ask1. How to compile Java files by codeThe compiler is a command-line tool (the JDK's own compilation tool, Javac, for Javac see here: What Javac is), but it can also be invoked using the API (the General IDE

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Here we first introduce the next callable and future, we know 2 ways to create threads, one is to inherit the thread directly, and the other is to implement the Runnable interface, but the threads created in both ways do not return results. While

Many years ago video of the same period seen a lot, horse soldiers, Zhang Xiaoxiang, Wang Yong, there are many.The horse soldier is the only one who at the time seemed to teach the beginner to understand that the others were not to let others

As with static variables, we can also use the static modification method, called a static method or a class method. In fact, the main method we've been writing about is static methods. The use of static methods such as:Operation Result:Need to note:1

Although the frequency of writing the shell is very low ... But every time you write a lot of jar file paths, the new jar package must also be modified to start the shell.Find a nice generic shell script on the web.Just modify some of the

In the previous article we learned about thread management for the executor framework, this article will learn about another feature of the executor framework, and we know that performing runnable tasks is not a worthwhile return, but executor can

Java garbage collection and Java garbage collection There are two steps for garbage collection:Method for Determining spam objects Which objects can be considered as "GC Roots" objects? Class-Objects loaded by the system class loader. These

Json and json online resolution Official network media type of json: application/json.The extension is. json. Is a data exchange format. Json Syntax:Data is represented by key/value pairsUse braces to save objects. Each name is followed by a ':'