You might want to change the behavior of a Java application at runtime without having to alter the original sources and recompile them. This can be done by using a Java Agent. Java Agents are used by several products. Dynatrace uses for example a Java Agent to collect data from inside […]
Software Development
Automating actions on Windows – my first steps with AutoIt
I recently spent quite some time on getting to know Playwright – a great tool for automating virtually any operation performed in a browser. Playwright is great for automating testing web applications as well as for screen scraping (for data), tactical integration, RPA, prototyping and even customizing third party applications […]
Python: A Google Translate service using Playwright
There are a lot of use-cases in which you might want to automate web-browser actions. For example to automate tedious repetitive tasks or to perform automated tests of front-end applications. There are several tools available to do this such as Selenium, Cypress and Puppeteer. Several blog posts (such as here) […]
Some end-of-year remarks about the AWS Shop Example
It is the end of the year: time to look back, time to look forward. In the past year, I had a lot of extra time because of the Corona measures. I spent most of that time creating blog articles about AWS, starting with a series about the AWS shop […]
Performance problems, the Whys.. and Hows.. around them
Introduction Over the last years, as part of my consultancy experience, I had the chance to work on several assignments tackling IT performance problems. In this post I will try to share my experiences on that topic, considering performance problems that I have faced on several (on-premise, cloud, hybrid) and […]
How to dynamically Schedule EM Blackouts after PatchTuesday
In the organization I’m currently working for, the OS-patch schedule depends on PatchTuesday (PT) just as Microsoft, Adobe or Oracle are using. And PatchTuesday is, as you all know, the Second Tuesday of each month. But this is a schedule you can not set in the Oracle Enterprise Manager Scheduler. […]
ADF Performance Monitor New Whitepaper Published
We are happy to announce that we have a new whitepaper on the ADF Performance Monitor. This blog publishes a new whitepaper that gives more information about the architecture, features and implementation of the ADF Performance Monitor. It is updated with the many features of our new major version 9.5. Recently […]
Quickly get going with Kotlin on Windows–using VS Code as IDE
Kotlin has been on my mind. The back of my mind, but still. And apart from a very short workshop last year at Devoxx I have not really tried it out. VS Code is my preferred IDE nowadays. So I wanted to get going with Kotlin in VS Code. Of […]
Run VS Code on Linux, in a container or just anywhere–work in a browser
My colleague pointed the open source code-server project to me. This project allows you to run Visual Studio Code just anywhere – and to develop on any device. He already had it running – showing off his code development skills on a mobile phone. Of course I had to try […]
ADF Performance Monitor: New Introduction Video (3:40)
Are you unable to pinpoint frustrating blind spots and recurring problems in your ADF application? This video gives a quick introduction of the features of the ADF Performance Monitor, an advanced monitor specifically designed for Oracle ADF applications.
Write debug level logs on error – print detailed logging only in exceptional circumstances
TL;DR: Collect debug information in an in-memory buffer that is printed to the output when an error occurs (and quietly discarded in all other cases). I may have come up with a useful idea. Or something that is not all that useful. Or even something that already exists (and I […]
Connect Azure Pipelines with sonarcloud through maven (YAML)
Introduction Sonarcloud is a static code analysis tool. This means that it checks out the code at your repository, does an analysis and shows you the results. It may look something like this: It gives detailed information about your code and you can for example let it scan if you […]
Productivity Boosting features in Windows 10
I ran into a valuable 17 minute YouTube movie with tips over some useful Windows 10 features: https://www.youtube.com/watch?v=do06MPWf9E4 I created this short list as a personal reminder: Virtual Desktop – multiple desktop pages for different circumstances (per customer, technology, work and private, for specific demos or recording webinars) (Windows + […]
ADF Performance Monitor: Thread Wait and Blocked Time
Last week we had a new version of the ADF Performance Monitor available – version 9.5. In this blog I will write on one of the new features; thread wait and thread blocked time of requests. Sometimes we cannot explain a poor performance, disruptions, hiccups. If we dive into the […]
ADF Performance Monitor New Version 9.5
We have again a major new version of the ADF Performance Monitor available – version 9.5 ! We have added many new valuable features and improvements. Many overview screens have got a facelift and new charts. In several blogs I will write on them. This blog is on one of […]
DIY Kafka Topic Watcher tool – Node, Express, Server Sent Events and Apache Kafka
This article can be read in at least two different ways: as a somewhat lengthy introduction of a handy tool that you can easily run to inspect messages published to the topics in a Kafka Cluster as a detailed yet basic example of how to combine several techniques to create […]
Spring: Blocking vs non-blocking: R2DBC vs JDBC and WebFlux vs Web MVC
Spring Framework version 5, released in Sept 2017, introduced Spring WebFlux. A fully reactive stack. In Dec 2019 Spring Data R2DBC was released, an incubator to integrate relational databases using a reactive driver. In this blog post I’ll show that at high concurrency, WebFlux and R2DBC perform better. They have […]
Migrating an old (10.2.0.4) database to Oracle Cloud with minimal downtime
Unlike most of our posts this post will contain almost no code or examples. But it hopefully will help somebody who ends up to be in the same situation we landed on: migrating data from very old versions to a new environment. Recently we were tasked with the migration of […]
The size of Docker images containing OpenJDK 11.0.6
When running Java applications in containers, you need to be careful with your resources. If you’re not careful with layering your images (for example using Google’s Jib), you can quickly get into disk-space issues, especially when your base image and/or application gets updated regularly. One of the ways you can save […]
Performance of relational database drivers. R2DBC vs JDBC
R2DBC provides non-blocking reactive APIs to relational database programmers in Java. It is an open specification, similar to JDBC. JDBC however uses a thread per connection while R2DBC can handle more connections using less threads (and thus potentially use less memory). This could also mean threads are available to do other […]
HTTP benchmarking using wrk. Parsing output to CSV or JSON using Python
wrk is a modern HTTP benchmarking tool. Using a simple CLI interface you can put simple load on HTTP services and determine latency, response times and the number of successfully processed requests. It has a LuaJIT scripting interface which provides extensibility. A distinguishing feature of wrk compared to for example ab […]
jq – Linux command line tool for interpreting and manipulating JSON documents
I am not the first to discover jq, or even to write about it. However, jq was such a valuable tool for me that I felt obliged to share it with you. And turn it into a Katacoda scenario (Katacoda is on of my other favorite finds). jq is a […]
Apache Camel + Spring Boot: Different components to expose HTTP endpoints
Apache Camel is an open source integration framework that allows you to integrate technologically diverse systems using a large library of components. A common use-case is to service HTTP based endpoints. Those of course come in several flavors and there is quite a choice in components to use. In this blog post […]
ADF Performance Monitor – Major New Version 9.0 (Part 1)
I’m very excited to announce that we have a major new version of the ADF Performance Monitor – version 9.0 ! We have added many valuable new features; new metrics that can detect and help explain poor performance, disruptions, hiccups, and help troubleshooting ADF applications. Like operating system metrics: the […]
Java Microservices: What do you need to tweak to optimize throughput and response times?
Performance tuning usually goes something like followed: a performance problem occurs an experienced person knows what is probably the cause and suggests a specific change baseline performance is determined, the change is applied, and performance is measured again if the performance has improved compared to the baseline, keep the change, […]
Performance! 3 reasons to stick to Java 8 for the moment
It is a smart thing to move to newer versions of Java! Support such as security updates and new features are just two of them but there are many more. Performance might be a reason to stick to Java 8 though. In this blog post I’ll show some results of […]
ADF Performance Monitor: Error Diagnostics
Application errors are often hard to retrieve, or take a lot of time to resolve. When you are suffering from errors, and have a lack of clarity when errors happen, you would like to have useful error diagnostics for analysis. The ADF Performance Monitor automatically captures detailed diagnostics for each […]
Customer Case: New Server Infrastructure Halves Server Process Time
Recently I was analyzing and troubleshooting the performance of an ADF application. Much was already improved before I came. Due to a very recent new hardware/infrastructure environment, the server and database process time was nearly 50% faster after migration. In this blog I want to show you the impact it […]
Building a RESTful Web Service with Spring Boot using an H2 in-memory database and also an external MySQL database
In a previous article, I talked about an environment, I prepared on my Windows laptop, with a guest Operating System, Docker and Minikube available within an Oracle VirtualBox appliance. In this article, I will create two versions of a RESTful Web Service Spring Boot application that, later on (in another […]
How to use any Oracle JET Component in VBCS
Oracle JET has more components than available in VBCS. Using Web Components you can extend VBCS yourself with the missing JET components. In Oracle JET you can add a Paging control to a table. For that you have to use a PagingDataSource. The Paging Control and PagingDataSource are (out of […]
ADF Performance Monitor brings performance improvements and Insight at Intris
Intris is the leading Belgian provider of freight forwarding, customs and warehousing management solutions. Headquartered in Antwerp, Intris provides its integrated software and cloud-based solutions to logistics services providers in Belgium and the Netherlands. Ben Rombouts is Chief Operating Officer at Intris. Recently he has written a detailed review on […]
Expose Docker Container services on the Internet using the ngrok docker image
The challenge: you are running a service, API or web application in a Docker container, locally on your laptop or in a cloud based VM or container platform. You would like to provide access to external consumers – yourself on your smart phone, a piece of code running in a […]
Don’t ask what you can do for documentation – ask what documentation can do for you! (a top down perspective on documentation)
How much documentation is enough documentation? What are the requirements in the definition of done regarding documentation? Cannot simply all code be self-documenting? These are common questions in DevOps, Scrum and other type of software development teams. Typically bottom up discussions among software developers at the time of developing the […]
JVM performance: OpenJ9 uses least memory. GraalVM most. OpenJDK distributions differ
In a previous blog post I created a setup to compare JVM performance of several JVMs. I received some valuable feedback on the measures I conducted and requests to add additional JVMs. In this second post I’ll look at some more JVMs and I’ve added some measures like process memory […]
Comparing JVM performance; Zulu OpenJDK, OpenJDK, Oracle JDK, GraalVM CE
There are many different choices for a JVM for your Java application. Which would be the best to use? This depends on various factors. Performance being an important one. Solid performance research however is difficult. In this blog I’ll describe a setup I created to perform tests on different JVMs […]
Monitoring Spring Boot applications with Prometheus and Grafana
In order to compare the performance of different JDKs for reactive Spring Boot services, I made a setup in which a Spring Boot application is wrapped in a Docker container. This makes it easy to create different containers for different JDKs with the same Spring Boot application running in it. […]
Running Reactive Spring Boot on GraalVM in Docker
GraalVM is an open source polyglot VM which makes it easy to mix and match different languages such as Java, Javascript and R. It has the ability (with some restrictions) to compile code to native executables. This of course offers great performance benefits. Recently, GraalVM Docker files and images have […]
Quick Start with Eclipse Che – Browser based IDE, running on Docker
One of the nice discoveries I made last week during CodeOne 2018 was Eclipse Che. This is a browser based polyglot IDE that runs in a Docker container – either locally, on a central server or in the cloud, on a stand alone Docker engine, a Kubernetes or an OpenShift […]
PeopleCounter part one: Counting People
Intro Internet of Things stands for connecting devices to the internet. The devices are then able to communicate with each other. In our project, the PeopleCounter, we use a mini-computer with intelligent software to count the number of people in front of a camera. We send that number to an […]
Oracle ADF Performance: Top 10 Typical Bottlenecks
In this blog I will discuss the top 10 typical performance problems I see in general in Oracle ADF projects – and will discuss solutions. Top 10 Typical Bottlenecks – Illustrated by ADF Callstacks I will illustrate the top 10 typical bottlenecks with ‘ADF callstacks’ – a feature of the ADF Performance […]