The Apache SkyWalking team today announced the 8.4 release is generally available. This release fills the gap between all previous versions of SkyWalking and the logging domain area. The release also advances SkyWalking’s capabilities for infrastructure observability, starting with virtual machine monitoring.


SkyWalking has historically focused on the tracing and…

Apache SkyWalking: an APM (application performance monitor) system, especially designed for microservices, cloud native, and container-based (Docker, Kubernetes, Mesos) architectures.

Envoy Access Log Service: Access Log Service (ALS) is an Envoy extension that emits detailed access logs of all requests going through Envoy.


Apache SkyWalking has long supported observability in…

Richard Feynman

In the previous post, we already have an EchoServer that is implemented with Java NIO; Let's check what we have and what we don't for now:

  1. All the IO operations (accept, read, write) are done when ready; there's no need to wait synchronously;
  2. No need to create thread for every…


This is a minimal yet complete and runnable project that gets you quickly start to build a project with GraphQL.

Available on GitHub:

How To Run

  • Clone the code to your local machine:
git clone
  • Run it:
mvn spring-boot:run
  • Play with it:

Open your browser and navigate to http://localhost:9092/gui

Create Authors

In the…

Richard Feynman

In the previous post, we’ve implemented an Echo Server by the Blocking I/O (BIO) library and discussed some of the disadvantages of BIO:

  1. Server thread cannot do anything but wait when accepting new connections.
  2. Clients must wait in queue to be served, OR tens of thousands of threads must be…

Richard Feynman

What is Netty

If you are a Java developer, you must have heard about Netty more or less, and it’s likely that you have used it, directly or indirectly. If not, there is a brief introduction from the Netty Project.

Netty project — an event-driven asynchronous network application framework.

Netty is an…

Build Your Own Netty — Start from BIO

Netty Project

In this article, we will implement an Echo Server by the Java Blocking I/O library.

Echo Server with BIO

1. listen on port 8080…

YASA is another Solr Admin built on VueJS and ECharts, greatly inspired by Kibana, which is a visualization tool for Elasticsearch. YASA aims to be “Kibana” for Solr eventually.




This story was originally posted on GitHub:


Caching is a critical technology in many high performance scalable applications. There are many choices in caching framework, including Ehcache, Memcache, cache2k etc. But today we are going to build one on our own, to learn what cache really does. …

EnumSet is a specialized implementation of java.util.Set, as its name implies, it is designed for use with Enums; so what’s the difference between EnumSet and a regular Set (say HashSet)? And why should we use EnumSet whenever possible instead of a regular Set?


Here are the environments used in this…


Apache SkyWalking Core Maintainer; Open-source enthusiast. GitHub@kezhenxu94

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