Setting up an OpenJ9 Development Environment with Visual Studio Code + Docker + CMake

Setting up a proficient development environment on a large project such as OpenJ9 with so many pieces in play can be a daunting task. Often times, setting up such a development environment and being able to navigate the codebase with familiar tools and with the full power of an IDE is worth the effort in terms of productivity. This blog post will guide you through setting up a development environment with a one-click build trigger, full Intellisense support, and full debugging support using Visual Studio Code, Docker, DevContainers extensions, and CMake.

Arraylets: What are They?

Garbage Collectors (GCs) are responsible for allocating and deallocating objects making sure the running application run as smoothly as possible. There are many types of GC configurations out there, mark sweep, generational, region based, concurrent, parallel, reference counting [1] and a combination of these. The way we represent objects in each of these configurations, also…

Manipulating the Class File with AsmTools

A Java class file is represented with a hardware & OS independent binary format to be loaded & interpreted at runtime. Except the magic number (the first 4 bytes such as CAFEBABE) and the version number (the 8th byte) which are visible or can be manually edited in a hexadecimal way, modifying the majority of…

Startup Performance of Tomcat in Docker

Tomcat startup time is reduced by ~30% by enabling the Shared Class Cache (SCC) in the Docker images. In my earlier blog , I measured the Performance of Tomcat with Tradelite7 Application without using any docker images and we saw the boost of Startup time with default Shared Cache in OpenJ9. In this article, let’s…

Default Java Maximum Heap Size is changed for Java 8

Background The Maximum Java Heap Size (Xmx) is the maximum amount of memory that Java application can uses. A lower Xmx value will cause a decrease in performance due to JVM has to force frequent garbage collections in order to free up space, also if the Xmx value is lower than the amount of live…