reflection mechanism

1, Reflection: 1. Reflection refers to a class that can be loaded, probed, and used at run time, completely unknown during compilation. 2. In the running state of the program, you can dynamically load a class with only a name. For any loaded class, you can know all the properties and methods of the class; For any object, you can call any of its ...

Posted on Mon, 24 Feb 2020 09:48:32 -0500 by benrussell

Java lock spin lock

1. What is spin lock                        . Because the thread keeps executing during this process, it is a busy wait. It is a non blocking lock, that is to say, if a thread needs to acquire a lock, but the lock has been occupied ...

Posted on Mon, 24 Feb 2020 01:33:30 -0500 by RedOrbit

Play with spring boot 2. X's fast integrated Jedis client (normal version)

Preface In Java development, you usually choose the Jedis client to perform Redis related operations. In this article, you can use the spring boot project to quickly start Jedis related operations. Code case Basic configuration operation The specific code is as follows: <dependency> <gro ...

Posted on Sat, 22 Feb 2020 07:29:31 -0500 by JunbinDuan

Design Mode_Singleton Mode

An overview of the singleton pattern 1. Core: Ensure that a class has only one instance and provide a global access point to that instance. 2. Advantages of the singleton mode: 1) The performance overhead of the system is reduced because the singleton mode only produces one instance object.When th ...

Posted on Fri, 21 Feb 2020 21:04:40 -0500 by khurramijaz

Microservice inheritance and composition: how to choose

Through the learning of Java framework, we learned about the basic methods of comparing two kinds of contact classes, and then practiced debugging ClassCastExceptions in Java inheritance. Inheritance and composition are two programming techniques used by developers to establish relationships between classes and objects. Inheritance is to inher ...

Posted on Tue, 18 Feb 2020 03:19:22 -0500 by lanrat

Fast learning - Hive enterprise level tuning

Chapter 9 enterprise level optimization 9.1 Fetch Fetch refers to the fact that some queries in Hive can be queried without MapReduce. For example: SELECT * FROM employees; in this case, Hive can simply read the files in the storage directory corresponding to the employee, and then output the query ...

Posted on Mon, 17 Feb 2020 22:19:15 -0500 by lazytiger

How Spring Boot gracefully stops services

Author: Yellowstone Source: Blog Park Preface When using Springboot, it involves stopping and starting the service. When we stop the service, many times everyone kills the program process directly by kill-9, so the program does not perform elegant shutdown.And some programs that have not finished executing will exit directly. Much of the tim ...

Posted on Sun, 16 Feb 2020 21:56:56 -0500 by RJP1

Enumeration in Java

1, What is enumeration? Enumeration is to enumerate one by one. It is often used to express those collections that can be clearly defined, such as gender, season, week, month, direction (East, West, North and South), etc. So the use scenario of enumeration is: when variables (especially parameters of ...

Posted on Fri, 14 Feb 2020 06:30:59 -0500 by delldeveloper

Alibaba talk to you about some JVM level locks of Java

brief introduction In the computer industry, there is a law called "Moore's law". Under this law, the performance of the computer is advancing rapidly, and the price is also getting cheaper and cheaper. The CPU is from single core to multi-core, and the cache performance is also greatly improved, especially the arrival of multi-core ...

Posted on Fri, 14 Feb 2020 05:49:49 -0500 by habanero25

Java 8 new features learning notes -- Optional Foundation

Preface As a Java programmer, you may have the experience of calling a method to get the return value, but you can't directly call other methods with the return value as a parameter. First of all, we need to determine whether the return value is null. Only when it is not empty can it be used as a parameter of other methods. It's something like ...

Posted on Wed, 12 Feb 2020 03:20:55 -0500 by Cal