JPA Pitfalls – a Series of Serious JPA Obstacles

Most of our Java-based web-applications store their data in a relational database such as Oracle, PostgreSQL, MySQL, MariaDB or MS SQLServer. The standard way to access and modify the data is using an object-relational mapping as specified by the Java Persistence API (JPA). Over the years JPA has become a mature specification and there are a couple of JPA implementations with strong support such as Hibernate, EclipseLink, OpenJPA and DataNuclues. However, day-to-day project experience demonstrates there are number of pitfalls you might run into when using JPA.

pitfall

To avoid stumbling into the same pitfall again and again, we collected them with their solutions and presented these pairs of problems and solutions. This is a start of a series of blog articles each describing a pitfall and a way to circumvent it.

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Part 1: GraphQL with Spring Boot, JPA and Kotlin

GraphQL is a query language for dynamic queries on linked data. In the GraphQL world, there are many tutorials and documentation that illustrate the concrete introduction to GraphQL. Since getting started requires a lot of explanation, regular tutorials usually have a simple setup, which does not reflect the real world complexity. If additional technologies are added or the complexity of the project increases, these “Hello World” examples are usually no longer so helpful.

This article introduces GraphQL on the technology Spring Boot with JPA and Kotlin. I also present some best practices which I have learned while I have worked with it. You can find the source code here: https://github.com/akquinet/kotlin-spring-graphql

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Monitoring the JBoss EAP / Wildfly Application Server with the Command Line Interface (CLI)

The JBoss EAP / Wildfly provides a powerful concept for management, configuration and monitoring of the JBoss Application Server itself and its Java EE Applications. The concept is based on the detyped management API. All management clients of the application server use this detyped management API to interact with the server.

In this post we focus on some useful runtime metrics which are of interest when monitoring your application server and application with the Command Line Interface (CLI).

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Use jBPM5 embedded within a Java EE 6 application

Since the first final release of jBPM5 at the beginning of 2011 a little more than one year has passed. Despite of being a final release there have been a couple of bugs and the documentation was having many deficiencies. During the last year, however, jBPM5 was quickly moving forward and many bugs were fixed and the documentation has significantly improved.

Notwithstanding the improvements there are still some points which are not covered by the documentation of which the most important one for us is the integration of jBPM5 into a Java EE6 application. In the past we had multiple Java EE 5 projects where jBPM3 could be easily integrated. This is something we want for the current amazing Java EE 6 stack. Unfortunately there is no documentation on how to achieve this goal – maybe because no one succeeded in implementing it? Therefore, we took on this challenge and found a solution which meets our requirements. In this blog post we will describe this solution. Before we start to describe our solution we want to briefly lay out the requirements of the integration of jBPM5 into a Java EE 6 application.
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