Programming VIP

1 what is generics 1.1 problems when not using generics Before JAVA introduced generics, you can store any data type Object by building a collection with the element type of Object. However, in the process of using the collection, you need to know the data type of each element. Otherwise, it is easy to cause ClassCastException exceptions. The ...

1 Introduction 1. What is it Hadoop is an open source software of apache for big data storage and computing. 2. What can I do a big data storage b distributed computing c (computer) resource scheduling 3. Features High performance, low cost, high efficiency and reliability. It is universal and simple to use 4. Version 4.1 open source communi ...

catalogue I What is Maven Maven project file structure: II Maven's configuration file - POM xml III Dependency management 1.maven warehouse 2. In POM Configure dependency in XML file IV Lifecycle and its related commands V Order in which Maven loads dependent packages I What is Maven Maven: project construction tool, packaging tool ...

registerListeners() of Spring source code and publish subscribe modeHello, I'm classmate Tian, a programmer.Today, let's explain the registerListeners() method in the refresh() method, which is often referred to as the publish subscribe mode of Spring. This paper first gives an example of publish subscribe mode, then explains the principles of ...

This blog will explain the String class in java in detail. Create string Common ways to construct String //Mode 1 String str = "hello"; //Mode 2 String str1 = new String("Hello"); //Mode 3 char[] array = {'a', 'b', 'c'}; String str2 = new String(array); be careful: String literal constants such as "hello" are also of type s ...

Interviewer: what are your commonly used encryption algorithms? Encryption algorithms are usually divided into two kinds: symmetric encryption algorithm and asymmetric encryption algorithm. The symmetric encryption algorithm uses the same key in encryption and decryption; Asymmetric encryption algorithm uses different keys in encryption and ...

JAVA object oriented Advantages of object orientation: Consistent with human thinking, "class" simulates abstract concepts in the real world, and "object" simulates entities in the real worldInformation hiding to improve the maintainability and security of the program: encapsulating the attributes and behaviors of the ...

What is an exception Abnormal situation An abnormal condition that occurs during the operation of a program, resulting in the unexpected termination of the program. How to handle exceptions In Java, the exception information is encapsulated into a class. When a problem occurs, it will create an exception class object and throw exception rela ...

Daily test Brief description of deadlock Which queues have you used This paper expounds the concept and basic use of process pool and thread pool What is a collaborative process and how to implement it simply summary """ Multithreading under multi process Reuse process under multithreading Maximum length can improve the efficiency ...

1, Object class 1.1 overview of object class Package: Java lang Class definition: public class Object Class Object is the root class of class hierarchy. Each class uses Object as superclass. All objects (including arrays) implement the methods of this class. Why define a hierarchy root class? Java believes that all objects have some basic ...