Saturday, March 17, 2018

Running Spring Boot in a Docker container on OpenJDK, Oracle JDK, Zulu on Alpine Linux, Oracle Linux, Ubuntu

Spring Boot is great for running inside a Docker container. Spring Boot applications 'just run'. A Spring Boot application has an embedded servlet engine making it independent of application servers. There is a Spring Boot Maven plugin available to easily create a JAR file which contains all required dependencies. This JAR file can be run with a single command-line like 'java -jar SpringBootApp.jar'. For running it in a Docker container, you only require a base OS and a JDK. In this blog post I'll give examples on how to get started with different OSs and different JDKs in Docker. I'll finish with an example on how to build a Docker image with a Spring Boot application in it.

Wednesday, March 14, 2018

Application Container Cloud Service (ACCS): Using the Application Cache from a Spring Boot application

Spring Boot allows you to quickly develop microservices. Application Container Cloud Service (ACCS) allows you to easily host Spring Boot applications. Oracle provides an Application Cache based on Coherence which you can use from applications deployed to ACCS. In order to use the Application Cache from Spring Boot, Oracle provides an open source Java SDK. In this blog post I'll give an example on how you can use the Application Cache from Spring Boot using this SDK. You can find the sample code here.

Thursday, February 22, 2018

Java: How to fix Spring @Autowired annotation not working issues

Spring is a powerful framework, but it requires some skill to use efficiently. When I started working with Spring a while ago (actually Spring Boot to develop microservices) I encountered some challenges related to dependency injection and using the @Autowired annotation. In this blog I'll explain the issues and possible solutions. Do note that since I do not have a long history with Spring, the provided solutions might not be the best ones.

Friday, January 26, 2018

Automate calls to SOAP and REST webservices using simple Python scripts

Probably not many people will tell you running batches over webservices is a good idea. Sometimes though, it can be handy to have a script available to generate webservice calls based on a template message with variables and automate processing the response messages. In addition, if you have a large number of calls, executing the calls in parallel might save you a lot of time if your service platform can handle the concurrency.

Tuesday, January 23, 2018

Getting started with Spring Boot microservices. Why and how.

In order to quickly develop microservices, Spring Boot is a common choice. Why should I be interested in Spring Boot? In this blog post I'll give you some reasons why looking at Spring Boot is interesting and give some samples on how to get started quickly. I'll shortly talk about microservices, move on to Spring Boot and end with Application Container Cloud Service which is an ideal platform to run and manage your Spring Boot applications on. This blog touches many subjects but they fit together nicely. You can view the code of my sample Spring Boot project here. Most of the Spring Boot knowledge has been gained by the following free course by Java Brains.


Friday, December 29, 2017

Getting started with Oracle Database in a Docker container!

One of the benefits of using Docker is quick and easy provisioning. I wanted to find out first-hand if this could help me get an Oracle Enterprise Edition database quickly up and running for use in a development environment. Oracle provides Docker images for its Standard and Enterprise Edition database in the Oracle Container Registry. Lucas Jellema has already provided two blogs on this (here and here) which have been a useful starting point. In this blog I'll describe some of the choices to make and challenges I encountered. To summarize, I'm quite happy with the Docker images in the registry as they provide a very easy way to automate the install of an EE database. You can find a Vagrant provisioning shell script with the installation of Docker and Docker commands to execute here and a description on how to use it here.

Sunday, December 10, 2017

10 reasons NOT to implement Blockchain now

A secure distributed ledger with smart contract capabilities not requiring a bank as an intermediary! Also a single source of truth with complete traceability. Definitely something we want! Blockchain technology promises to make this possible. Blockchain became famous through cryptocurrency like Bitcoin and Ethereum. The technology could also be considered to replace B2B functionality. With new technologies it is not a bad idea to look at pro's and con's before starting an implementation. Blockchain is the new kid on the block and there is not much experience yet on how well he will play with others and will mature. In this blog I summarize some of my concerns concerning blockchain of which I hope will be solved in due time.

Regarding new/emerging technologies in the integration space, I'm quite open to investigate the potential value which they can offer. I'm a great proponent of for example Kafka, the highly scalable streaming platform and Docker to host microservices. However, I've been to several conferences and did some research online regarding blockchain and I'm sceptical. I definitely don't claim to be an expert on this subject so please correct me if I'm wrong! Also, this is my personal opinion. It might deviate from my employers and customers views.

Most of the issues discussed here are valid for public blockchains. Private blockchains are of course more flexible since they can be managed by companies themselves. You can for example more easily migrate private blockchains to a new blockchain technology or fix issues with broken smart contracts. These do require management tooling, scripts and enough developers / operations people around your private blockchain though. I don't think it is a deploy and go solution just yet.