Java

First, callable and RunnableLet's talk about Java.lang.Runnable, it's an interface that only declares a run () method in it: Public Interface Runnable { publicabstractvoid run ();}Because the run () method returns a value of type void, No

As far back as the JDK version 1.4, there was no concept of generics at that time. The code for Java programmers writing collection classes was similar to the following:List list = new ArrayList();list.add("www.cnblogs.com");list.add(23);String name

The file class can operate on files in the operating system:Static member variable for file class: Packagedemo;ImportJava.io.File; Public classFiledemo { Public Static voidMain (string[] args) {//static methods for file classesString separator =File.

1. Login JekinsPrerequisite: Jekins has been deployed and can log inVersion: Jenkins2.60.2Http://IP: Port/jenkins/view/all/newjob2. Create a new Build taskSelect the type of project, select "Build a multi-configuration item" and enter the custom

"Java Learning" "-xmx1024m-xms1024m-xmn512m-xss256k"--java run parameters reprinted June 13, 2016 19:33:38 2792 Young generation concept of the old generation/HTTP The memory of the heap of the jefferent.iteye.com/blog/1123677 JVM is the size of the-

1. First use the command line to enter the folder where A.java is located: (for example, my D:\javaeeworkspace\SharedPS_WS\src\com\dyf\main in a path like this)D: Enter,CD D:\javaeeworkspace\SharedPS_WS\src\com\dyf\main Enter,2. Run the A.java

The string type in Java has a method of equals that can be used to infer whether two strings are equal, but such equality is different from the "equality" inferred by the operator = =, followed by the analysis, and the result is validated by the

The Graphics class can be interpreted as a brush. It is a drawing class that Java provides for us. Use it to draw: straight drawLine (int x1, int y1, int x2, int y2) rectangle drawrect (int x, int y, int width, int height) round drawoval (int x, int

1.while Cycle Structure　　Grammar: while (loop condition) { // loop Action }　　While loop structure Flowchart:　　Example:1 int i = 1; 2 while (i ) {3 System.out.printlen ("good study"); 4 i + +; 5 }Note: The content in the parentheses after the

Previously thought the This keyword refers to the caller object, but this time really understand that this represents the current object, but point to the caller object, is actually a polymorphic usage, as follows: B inherits A, in B calls a method

One, the visibility of the volatile keywordTo understand the volatile keyword, first understand the Java memory model, the Java memory model is abstracted as follows:Can be seen:① each thread has its own local memory space-the line stacks space???

There are three types of looping structures in Java:1.while CycleThe basic expression of the while loop:while (Boolean expression) {Looping content}As long as the Boolean expression ==true, the loop will always executeE.G1:class TestLoop{ public

What are the consequences of encountering abnormal abuses in the project code recently?1. Code readability is poor, business logic is difficult to understandThe exception flow is mixed with the business state flow and cannot understand the business

Describes the practice of Elastic Search engine in SpringBoot. Lab Environment ES version: 5.3.0 Spring bt version: 1.5.9 First of all, we need to install the elastic search environment. We 'd better install the visualization plug-in

Struts2 validation. xml verification rule code parsing, When using the validation. xml of struts2 for verification, pay attention to the following aspects: I. First, pay attention to the validation. xml name. You must add "-validation. xml" to the

Combing Servlet and JSP (1), servletjsp I had a JSP course in the first semester of my sophomore year, but I had a small JSP project before the start of school, so I didn't listen to the course for one semester until the final exam score came out, I

Java learning notes 41 (Properties class), learning notes properties Properties enables persistent storage of collection data It is an implementation class of the map interface. You can use the map class method, But there is a difference: it does

Java 8 has a simple understanding of Lambda expressions and functional interfaces. Java 8 is called the largest version ever changed in Java history. There are many important new features. The core is to add Lambda expressions and StreamAPI. The two

Deep understanding of building and introducing Maven environments, and deep understanding of building maven Maven is a Java tool for project management. In JavaEE, we can use Maven to conveniently manage projects in team collaboration. Now we are

Java learning notes 9 (Object-Oriented 2), java learning notes Proximity principle: When the names of the variables in the method and member variables in the class are the same, the variables in the method take effect when the class method is called.