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 […]
Software Development
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, […]
The state of Java [developers] – reflections on Devoxx 2019
![The state of Java [developers] – reflections on Devoxx 2019](https://technology.amis.nl/wp-content/uploads/2019/11/image-4-768x366.png)
I attended Devoxx Belgium – November 2019. The yearly gathering of over 3000 Java developers (numbers provided by Devoxx website). Maybe not all of them Java and perhaps some not even developers. But by and large … Java and software development are the core themes. This conference has taken the […]
Oracle Database: Write arbitrary log messages to the syslog from PL/SQL
Syslog is a standard for message logging, often employed in *NIX environments. It allows separation of the software that generates messages, the system that stores them, and the software that reports and analyzes them. Each message is labeled with a facility code, indicating the software type generating the message, and assigned […]
Calling out from Java to JavaScript (with call back) – leveraging interoperability support of GraalVM
Interoperability from Java to JavaScript has been an objective for the Java community for quite a while. With Rhino and later Nashorn, two valiant attempts were made to add scripting interaction to the JDK and JVM. Now, with GraalVM, there is a better alternative for running JavaScript code from within […]
Calling an Oracle DB stored procedure from Spring Boot using Apache Camel
There are different ways to create data services. The choice for a specific technology to use, depends on several factors inside the organisation which wishes to realize these services. In this blog post I’ll provide a minimal example of how you can use Spring Boot with Apache Camel to call […]
Microservice framework startup time on different JVMs (AOT and JIT)
When developing microservices, a fast startup time is useful. It can for example reduce the amount of time a rolling upgrade of instances takes and reduce build time thus shortening development cycles. When running your code using a ‘serverless’ framework such as for example Knative or FnProject, scaling and getting […]
Apache Camel and Spring Boot: Calling multiple services in parallel and merging results
Sometimes you have multiple services you want to call at the same time and merge their results when they’re all in (or after a timeout). In Enterprise Integration Patterns (EIP) this is a Splitter followed by an Aggregator. I wanted to try and implement this in Spring Boot using Apache Camel so I […]
A transparent Spring Boot REST service to expose Oracle Database logic
Sometimes you have an Oracle database which contains a lot of logic and you want to expose specific logic as REST services. There are a variety of ways to do this. The most obvious one to consider might be Oracle REST Data Services. ORDS is quite powerful and for example supports […]
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 […]
Devoxx Belgium 2018, From Developers For Developers
Last November, I attended the Devoxx Belgium 2018 event. In this article I gathered some practical information about the event, and the sessions that were held. Perhaps this gives you more insight in what you can expect from such an event and it may help you in deciding if, as […]
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 […]
Jenkins 2.0 pipeline: Scripting active parameters for SCM
Last year I got introduced to the new features 2nd generation Jenkins at a workshop of CloudBees . This year I got also the opportunity to discover them in practice. One of the most interesting and often challenging part of working with scripted pipelines is the gap between the list of plugins supported […]
Java programs as native executables: GraalVM is the answer!
TL;DR: • Using GraalVM Java applications can be compiled into native standalone executables (will be demonstrated). • Native executables of small Java programs startup blazingly fast, use considerably less resources compared to running on JVM and do not even require the JRE or any other kind of runtime apart from […]
ADF Performance Tuning: A Field Report
Last week I was doing an extensive performance analysis / health check on a large ADF project, with the newest version of our ADF Performance Monitor product. In this performance assessment/analysis I have focused high-level on the most important performance bottlenecks. We could see in the ADF Performance Monitor that end-users experience […]
Running Spring Tool Suite and other GUI applications from a Docker container
Running an application within a Docker container helps in isolating the application from the host OS. Running GUI applications like for example an IDE from a Docker container, can be challenging. I’ll explain several of the issues you might encounter and how to solve them. For this I will use […]
Automate the installation of Oracle JDK 8 and 10 on RHEL and Debian derivatives
Automating the Oracle JDK installation on RHEL derivatives (such as CentOS, Oracle Linux) and Debian derivatives (such as Mint, Ubuntu) differs. This is due to different package managers and repositories. In this blog I’ll provide quick instructions on how to automate the installation of Oracle JDK 8 and 10 on […]
ADF Performance Monitor: Monitoring with Percentiles
What is best metric in performance monitoring – averages or percentiles? Statistically speaking there are many methods to determine just how good of an overall experience your application is providing. Averages are used widely. They are easy to understand and calculate – however they can be misleading. This blog is on […]