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  New features in Java 9

Java 9 is planned to be released in March 2017. It will be 3 years since Java 8 was released. Are you still excited about the new features introduced in Java 8 such as Lambda, new Date APIs etc? Now Java 9 is to be released and there are also quite a few fantastic new features to be introduced. Below is a list of major new features in Java 9. Modular system. Java 9 will introduce a brand new modular system to organize Java codes. The modular system will divide different packages into diffe...

   JAVA,NEW FEATURE,JAVA 9     2016-04-05 09:56:01

  Will nil == nil be true in GoLang

There is some interview question may ask whether nil == nil be true in GoLang. Wil it be true. false or compilation error? To know the answer, some knowledge about nil in GoLang needs to be explained first. nil definition According to Go's official documentation, the definition of nil is // nil is a predeclared identifier representing the zero value for a // pointer, channel, func, interface, map, or slice type. var nil Type // Type must be a pointer, channel, func, interface, map, or slice type...

   GOLANG,NIL,NIL EXPLANATION     2021-08-08 02:54:15

  Install and setup Kafka on Windows

Kafka has become a very popular distributed message delivery service which decouples different services while making message delivery between service easy, fast and reliable. In this post, we will walk through how to install and set up Kafka on Windows. Pre-requisite Java Apache ZooKeeper Installation Go to Kafka's download link and download the latest stable release, we downloaded 2.2.0 as of this writing. After downloading, copy the installation file to some folder and unzip it.  Sinc...

   KAFKA,STREAM,USER GUIDE     2019-06-01 02:12:07

  One Way to Quickly Locate SQL with High CPU Usage in MySQL

When the CPU usage of a MySQL database rises abnormally, it's necessary to quickly identify the problematic SQL statements. In this post, we try to provide one way to achieve this.  Below are the actual steps. 1. Use the top command to find the threads with the highest CPU usage in the MySQL process. # Find the MySQL process ID ps -ef | grep mysql # Use the process ID to find the thread IDs with the highest CPU usage: top -H -p In top, press P to sort by CPU usage. Note the thread ID, fo...

   MYSQL,DEBUG,HIGH CPU,SLOW QUERY     2024-08-01 21:25:48

  Java AbstractMethodError explained and demonstrated

According to Oracle Java API documentation, AbstractMethodError is a kind of runtime error where the application is having some incompatible changes which leads to a missing implementation of an abstract method. Below is the official description. Thrown when an application tries to call an abstract method. Normally, this error is caught by the compiler; this error can only occur at run time if the definition of some class has incompatibly changed since the currently executing method was last co...

   JAVA,ABSTRACTMETHODERROR     2016-07-22 22:03:20

  Why is single threaded Redis so fast

Redis is a high-performance, in-memory key-value database. According to official test reports, it can support around 100,000 QPS (queries per second) on a single machine. However, Redis uses a single-threaded architecture in its design. Why does Redis still have such high performance with a single-threaded design? Wouldn't it be better to use multiple threads for concurrent request processing? In this article, let's explore why Redis has a single-threaded architecture and still maintains its spe...

   REDIS,SINGLE-THREADED,MULTI-THREADING     2023-02-28 05:16:22

  How to install Oracle database on Linux using response file

There are two ways to install Oracle database on Linux :1). Using GUI; 2). Using response file. In this post, the method for using response file will be introduced. To install Oracle, please first get the Oracle database installation file ready. It can be downloaded from Oracle OTN. You need to have an Oracle account before you can download them. And there are three major components of the Oracle database installation : 1). The installation itself; 2). The network configuration; 3). Database cre...

   LINUX,HOW TO,ORACLE DATABASE     2017-06-03 04:15:49

  GitHub launches a separate training page

Code hosting community Github has much proud data: 55 employees, Andreessen Horowitz promised a $100 million investment, $750 million valuation, a place developers stay longest since its launch in 2008 ... Github announced the official launch of a separate teaching page, to teach developers collaborative programming through various forms. Github announces the detail about the training program on its official blog, the entire training project has two modes : free and paid. The content of their t...

   GitHub,Training,Open source     2012-10-07 05:45:47

  Update & Delete Kubernetes resources in one-line command

It recently troubles me that my GKE cluster is managing more and more resources and causing difficulties in maintenance, one of which involves how to delete resources properly. Next, I will explain step by step the difficulties I encountered in my work and how I finally used the combination of bash commands and kubectl to implement the edition of Kubernetes objects through one-line command. In general The following are the basic operations that almost every Kubernetes user takes. Check ðŸ‘â€...

   KUBERNETES     2020-11-01 04:16:47

  etcd installation and usage

etcd is an open source and highly available distributed key-value storage system and is commonly used in critical data storage and service discovery and registration use cases. It is focusing on: Simple: well-defined, user-facing API (gRPC) Secure: automatic TLS with optional client cert authentication Fast: benchmarked 10,000 writes/sec Reliable: properly distributed using Raft etcd and Redis both support key-value storage and can be set up in distributed systems. Also Redis supporst more key...

   ETCD,TUTORIAL,RAFT,DISTRIBUTED SYSTEM     2021-03-07 03:10:33

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