Handle HTTP PATCH request with Java Servlet

The Java Servlet specification does not include handling a PATCH request. That means that class  javax.servlet.http.HttpServlet does not have a doPatch() method, unlike doGet, doPost, doPut etc.

That does not mean that a Java Servlet can not handle PATCH requests. It is quite simple to make it do that.

The trick is overriding the service(request,response) method – and have it respond to PATCH requests (in a special way) and to all other (more...)

Oracle Managed Kubernetes Cloud– First Steps with Automated Deployment using Wercker Pipelines

imageOracle announced a managed Kubernetes Cloud service during Oracle OpenWorld 2017. This week, I had an opportunity to work with this new container native cloud offering. It is quite straightforward:

Through the Wercker console

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a new Cluster can be created on a Oracle BareMetal Cloud (aka Oracle Cloud Infrastructure) environment. The cloud credentials are provided

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Name and K8S version are specified:

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The Cluster Size is configured:

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And the node configuration is indicated:

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Subsequently, Oracle will (more...)

Implementing Authentication for REST API calls from JET Applications embedded in ADF or WebCenter Portal using JSON Web Token (JWT)

imageThe situation discussed in this article is as follows: a rich client web application (JavaScript based, could be created with Oracle JET or based on Angular/Vue/React/Ember/…) is embedded in an ADF or WebCenter Portal application. Users are authenticated in that application through a regular login procedure that leverages the OPSS (Oracle Platform Security Service) in WebLogic, authenticating against an LDAP directory or another type of security provider. The embedded rich web application makes calls to (more...)

Microservices and Updating Data Bound Context on Oracle Cloud with Application Container and Event Hub (plus DBaaS and MongoDB)–Part Two

This article describes – in two installments – how events are used to communicate a change in a data record owned by the Customer microservice to consumers such as the Order microservice that has some details about the modified customer in its bound context. The first installment described the implementation of the Customer microservice – using MongoDB for its private data store and producing events to Event Hub cloud service to inform other microservices about (more...)

Microservices and Updating Data Bound Context on Oracle Cloud with Application Container and Event Hub (plus DBaaS and MongoDB)–Part One

This article describes – in two installments – how events are used to communicate a change in a data record owned by the Customer microservice to consumers such as the Order microservice that has some details about the modified customer in its bound context.

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The microservices are implemented using Node. The Customer microservice uses a cloud based MongoDB instance as its data store. The Order microservices runs on Oracle Application Container Cloud and has a (more...)

Prepare and link bind Oracle Database Cloud, Application Container Cloud, Application Container Cache and Event Hub

A fairly common combination of Oracle Public Cloud services that I use together – for example for the implementation of microservices – is DBaaS, Application Container Cloud, Application [Container] Cache and Event Hub. In this article, I show the sequence of steps I went through in the Oracle Public Cloud console a few days back to prepare a demo environment for my presentations at Devoxx Morocco in Casablanca. Alternatively, I could have used the command (more...)

Online Videos with Lucas Jellema–Live recording of Talks, Interviews and Stuff

An overview of some of my recent recordings:

expected soon:

November 2017 – Oracle Developer Community Podcast  What’s Hot? Tech Trends That Made a Real Difference in 2017 (with Chris Richardson, Frank Munz, Pratik Patel, (more...)

Run Oracle Database in Docker using prebaked image from Oracle Container Registry–a two minute guide

imageThis article will show how to run an Oracle Database on a Docker host using the prebaked images on Oracle Continer Registry. It is my expectation that it takes me very little manual effort to run the full 12.2.0.1 Oracle Enterprise Database – just pull and run the Docker image. Once it is running, I get the usual Docker benefits such as clean environment management, linking from other containers, quick stop and (more...)

Quick introduction to Oracle Container Registry–running one of Oracle’s prebaked images

Oracle has been active with Docker for quite some time now. From the first hesitant steps from some enthusiastic employees with Docker build files that helped people to get going with Oracle software in their experimental containers to a GitHub repo with a broad set of extensive Docker build files to create Docker containers with various Oracle product that are supported (https://github.com/oracle/docker-images). And of course the Oracle Container Cloud – launched in (more...)

First steps with Istio on Kubernetes on Minikube on Windows 10

In this article, I discuss my steps to get going with Istio [service mesh]on Kubernetes running on Minikube on Windows 10. Unfortunately, I have ran into an issue with Istio. This article describes the steps leading up to the issue. I will continue with the article once the issue is resolved. For now, it is a dead end street.

Note: my preparations – install Minikube and Kubernetes on Windows 10 are described in this previous (more...)

Installing Minikube and Kubernetes on Windows 10

Quick notes on the installaton of Minikube for trying out Kubernetes on my Windows 10 laptop (using VirtualBox –not Hyper-V)

Following instructions in https://www.ibm.com/support/knowledgecenter/en/SS5PWC/minikube.html 

Download Windows installer for MiniKube:

https://github.com/kubernetes/minikube/releases

Run installer

After running the installer, open a command line window

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Download kubectl.exe

curl -o kubectl.exe https://storage.googleapis.com/kubernetes-release/release/v1.8.0/bin/windows/amd64/kubectl.exe

Copy downloaded file to a proper location – of your choosing – and add that location (more...)

Rapid first few steps with Fn – open source project for serverless functions

Project Fn is an open source project that provides a container native, poly-language, cloud agnostic (aka run on any cloud) serverless platform for running functions. Fn was launched during Oracle OpenWorld 2017. Fn is available on GitHub (https://github.com/fnproject/fn ) and provides all resources required to get started. In this article, I will just show you (and myself) how I went through the quick start steps and what it looked like on my laptop (more...)

Create Debian VM with Docker Host using Vagrant–automatically include Guest Additions

A short and simple article. I needed a Debian VM that I could use as Docker host – to run on my Windows 10 laptop. I resorted to Vagrant. With a few very simple steps, I got what I wanted:

0. install Vagrant (if not already done)

0. install Vagrant plugin for automatically adding Virtual Box Guest Additions to every VM stamped out by Vagrant (so folder mapping from host laptop to VM is supported)

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(more...)