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Java Developers

A group for Java developers on the islands.

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Latest Activity: Apr 10, 2017

Discussion Forum

JPA? 4 Replies

Started by George. Last reply by George Mar 4, 2012.

Java in Decline? 6 Replies

Started by Daniel Leuck. Last reply by Daniel Leuck Mar 4, 2012.

It's been a long time coming, but Java 7 is finally with us 1 Reply

Started by Paul Graydon. Last reply by Daniel Leuck Jul 28, 2011.

Java Developer News

The JDKs: Which One to Use?

Recently (or not so much), Oracle announced that it will change the way Java evolves, adopting the "Release Train" to launch new versions. In addition, it has changed the way support for the versions will be offered, providing only support for LTS versions (which will be every three years, see Java 8, 11, and so on). The community made up of the Java Champions also spoke about it, explaining the changes in detail here.

However, along with this news, how are JDK builds available? Will they be free or paid? Before answering this, it's important to understand what a "valid" JDK for distribution actually means. In practical terms, there is only one set of source code for the JDK. The source code is hosted here. Anyone can pick up this source code, produce a build, and post it to a URL. However, there is a separate certification process that must be used to ensure that construction is valid. Certification is performed by the Java Community Process (JCP), which provides a Technology Compatibility Kit (TCK). If an organization produces an OpenJDK build that complies with the entirely TCK, this build may be described as "compatible with Java SE".

The JVM Advent Calendar: JCP.NEXT, Streamlining the JCP Program

Java Community Process (JCP) version 2.11, with a focus on streamlining the JCP program takes effect December 14th.

This blog post is on the latest JCP.Next effort to streamline the JCP program JSR lifecycle in response to feedback from the Java development community and the faster release cadence introduced in 2017.

Installing Maven With Your JDK

Apache Maven is distributed in several formats. The simplest way to install Maven is to download a ready-made binary distribution archive and follow the installation instructions. Maven 3.3+ release requires JDK 1.7 or above to execute

General Requirements

  • Java JDK must be installed on your system.
  • Java 1.7 or higher is needed for Maven.

To verify the Java JDK is properly installed, from your command line, run the following command:

How to Fix Invalid Target Release: 1.7, 1.8, 1.9, or 1.10 Error in Maven Build

If you are building your Java project using Maven, in Eclipse, or from the command prompt by running mvn install and your build is failing with an error like "invalid target release: 1.7" or "invalid target release: 1.8," then you have come to the right place. In this article, I'll show you why this error occurs and how you can deal with these errors even with higher Java versions, like Java 9 or 10, installed on your machine. The root cause of the problem is that you have specified a higher Java version in your pom.xml file for Maven compiler plugin than what Maven knows in your system, and that's why it's saying invalid target release.

A simple solution to this problem is either to reduce your target version in pom.xml or install a new Java version if you want to build your project in a higher version.

Behavioral Design Patterns: Observer

The observer is one of the most popular design patterns. It has been used on many software use cases and, thus, many languages out there provide it as a part of their standard library.

By using the observer pattern, we can tackle the following challenges.

Comment Wall


You need to be a member of Java Developers to add comments!

Comment by Vern Takebayashi on April 24, 2010 at 8:27pm
Yes, you are correct about Jackson being able to produce that output. The main reason why I put the toString() method in, is that I usually require that my students write that method for any basic storage class that they write. I think Jackson will get a fair amount of usage, especially since it is one of the best performing Java JSON parsers.
Comment by Les Vogel on April 24, 2010 at 3:10pm
Cool. I've been using org.json which while fairly tiny, is really annoying to use. Jackson looks like it produces more of what one would like.

I imagine that your toString method could easily ask Jackson to do that for you with a lot less code, but at the expense of order.
Comment by Vern Takebayashi on April 24, 2010 at 2:57pm

I did not see much about JSON parsing in Java. Here is a PDF file json-parsing-with-jackson.pdf that I just wrote for my ICS 111 course, that uses the Jackson Java JSON parser () If any of you care about JSON parsing in Java, I would appreciate feedback on this handout.

Comment by Stephen McMahon on April 1, 2009 at 3:01pm
Here's a good GWT presentation that I stumbled upon yesterday:

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