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SymmetricDS is web-enabled, database independent, data synchronization/replication software. It uses web and database technologies to replicate tables between relational databases in near real time. The software was designed to scale for a large number of databases, work across low-bandwidth connections, and withstand periods of network outage. By using database triggers, SymmetricDS guarantees that data changes are captured and atomicity is preserved. Support for database vendors is provided through a Database Dialect layer, with implementations for MySQL, Oracle, SQL Server, PostgreSQL, DB2, Firebird, HSQLDB, H2, and Apache Derby included. Synchronization can be configured to push data (trickle-back) or pull data (trickle-poll) at an interval. SymmetricDS allows for synchronization between two or more tiers of nodes, such as the following: A farm of web server nodes fronting an enterprise-class general office database A handful of regional servers for synchronizing from the general office to remote geographical areas 1000(s) of store server nodes using a departmental class database to sync with a regional node 10(s) of Point of Sale (POS) register nodes using an embedded database to sync with a store server Deployment options include the following: Web application archive (WAR) deployed to an application server such as Tomcat, Jetty, or JBoss Standalone service Embedded in an application SymmetricDS is written in Java and licensed as open source software under the GNU Lesser General Public License (LGPL).

"SwitchYard is a lightweight service delivery framework providing full lifecycle support for developing, deploying, and managing service-oriented applications. Wait, what? You mean like an Enterprise Service Bus (ESB)? Yeah, kind of. At it's core, SwitchYard provides an embeddable services runtime with limited dependencies, allowing you to deploy and run services where you need them: inside unit tests, embedded in your own applications, as modules in an OSGi framework, or within an application server. Of course, there will be modular components on top of core to provide connectivity, transformation, routing and orchestration, and all the other features that are typically associated with an ESB. The main difference between SwitchYard and traditional ESB offerings is that we are trying to make the runtime a transparent detail in the service lifecycle. SwitchYard aims to keep you focused on your services by providing tooling to help define, test, and manage the important details of a service - it's contract, policies, configuration, composition, and management . After all, the least important detail of your service is where it runs."

Apache ServiceMix is an open source ESB (Enterprise Service Bus) that combines the functionality of a Service Oriented Architecture (SOA) and an Event Driven Architecture (EDA)  to create an agile, enterprise ESB. Apache ServiceMix is an open source distributed ESB built from the ground up on the  Java Business Integration (JBI) specification JSR 208 and released under the Apache license. The goal of JBI is to allow components and services to be integrated in a vendor independent way, allowing users and vendors to plug and play.

Vaadin is a Rapid Application Development (RAD) framework for RIA applications. I only know it for a few months but since I started experimenting with it, I'm really in favor of it. I see a lot of advantages compared to Sun's Java EE standard front-end framework JSF. First of all Vaadin is a java library, so you only have to write Java to build a complete frontend. No need for a specific frontend language, no need for converters (for comboboxes),… This also implies that you can use the full Java power on the frontend side and that's an huge advantage because frontend code is now type-safe and easily refactorable. You can unit test your frontend with JUnit. You can also use all existing java libraries on the frontend side, for example LOG4J. Another advantage is the fact that Vaadin is easy to learn (JSF isn't!) and to use: it's straigtforward. It feels like developing desktop apps and for me developing desktop apps feels much more intuitive than developing web-apps the way I'm used to. Vaadin uses convention over configuration. No need to register new components, validators or whatever in different xml files. Themes have a default folder and a default folder structure. Vaadin is very well documented. There's the book of Vaadin wich explains every aspect of the framework very clear. On the site there's a blog, a FAQ section, a wiki, a forum, examples with Java source code, … It's very easy to extend. Want to create your own Validator? Just implement an interface or extend another Validator and use it. Want to create your own custom server side component? Just extend the CustomComponent class or extend from another component. There's also an add-on directory where you can download UI components, data components, tools, themes, …

"I've had an opportunity recently to work on a product that needed an RIA web interface, and I chose my recent favorite tool for this, Vaadin. The services for this project needed to be highly scalable, and lent themselves well to functional techniques, so I selected Scala as my language of choice. I build my projects with Maven, for reasons I won't go into right now, and I do much of my JVM-language work in Intellij's excellent IDEA IDE. Given these tools, I found a way to facilitate very rapid development of web UI's, and I thought I'd pass it along. Another technique I use, which I'll expound on later, is creating "dummy" implementations of all of my backing services for my application. The "real" implementations are written as OSGi services, in separate modules from my UI. The UI is packaged as a war, but is also OSGi aware, with a bundle activator. This activator only gets called if the war is deployed into an OSGi container, and not otherwise. This allows the app to select which implementation of the services it uses - the "dummy" ones when it's deployed outside of OSGi, and the "real" ones when they're available. This means I can use the handy Maven jetty plugin to quickly spin up my application and test it on my local workstation, without needing all of the dependencies (like a data store and such) of my real services. That's good, in that I can get my "cycle time" down to a few seconds, where "cycle time" is the time between making a change and actually being able to test it in my browser. We can do better, though. I'm using Scala as my language of choice for building the UI as well, as it works just fine with Vaadin (and with everything else in the JVM ecosystem, for that matter, which is why I didn't choose a non-JVM language - but that's yet another rant). I compile my Scala with the Maven scala plugin - here's where the next handy bit comes into play. Turns out the Scala plugin has a goal cal

Last week I decided to challenge Scala's downscalability by trying to replace a Groovy script with a Scala pendant. In this article you will read about this little experiment and a comparision of the Scala result with the Groovy predecessor. But first some background about the script: Some time ago my company introduced a new spam notification system.  When it thinks that a mail contains spam, it keeps it in quarantine and once or twice a day sends an email to the recipient (me) reporting all the kept mails, together with an intranet web link for each  to release it. Here you see an example of such a mail (note: I have my mails displayed in plain text format):

ModeShape (formerly "JBoss DNA") is a JCR 2.0 (JSR-283) implementation that provides access to content stored in many different kinds of systems. A ModeShape repository isn't yet another silo of isolated information, but rather it's a JCR view of the information you already have in your environment: files systems, databases, other repositories, services, applications, etc. To your applications, ModeShape looks and behaves like a regular JCR repository. Using the standard JCR API, applications can search, navigate, version, and listen for changes in the content. But under the covers, ModeShape gets its content by federating multiple back-end systems (like databases, services, other repositories, etc.), allowing those systems to continue "owning" the information while ensuring the unified repository stays up-to-date and in sync. ModeShape repositories can be used in a variety of applications. One of the most obvious ones is in provisioning and management, where it's critical to understand and keep track of the metadata for models, database, services, components, applications, clusters, machines, and other systems used in an enterprise. Governance takes that a step farther, by also tracking the policies and expectations against which performance can be verified. In these cases, a repository is an excellent mechanism for managing this complex and highly-varied information. But a ModeShape repository doesn't have to be large and complex: it could just manage configuration information for an application, or it could just provide a JCR interface on top of a couple of non-JCR systems.

"Learn how to use EMF.Edit and Common Navigator Framework (CNF) to create a model navigation plug-in based on a tree viewer. Build an Eclipse plug-in that allows users to manipulate and navigate the content of an Eclipse Modeling Framework (EMF)-based model. This will involve step-by-step guidance of developing the plug-in, implementing the proper structures to extract the model content through the EMF edit framework, and displaying the content in a CNF-based view part."

Apache Axis is an implementation of the SOAP ("Simple Object Access Protocol") submission to W3C. From the draft W3C specification: SOAP is a lightweight protocol for exchanging structured information in a decentralized, distributed environment. It is an XML based protocol that consists of three parts: an envelope that defines a framework for describing what is in a message and how to process it, a set of encoding rules for expressing instances of application-defined datatypes, and a convention for representing remote procedure calls and responses. This project is a follow-on to the Apache SOAP project. Please see the Reference Library for a list of technical resources that should prove useful.

WeWebU OpenWorkdesk is an application suite (not just a CMIS browser!) for Enterprise Content Management (ECM) with an intuitive Web 2.0 front-end. OpenWorkdesk applications are future-proof and protect your investments because the user interface and the application layer have been separated from the underlying ECM system. This separation allows you to continue using your applications without laborious modifications even after an upgrade or change of the ECM platform. OpenWorkdesk Community Edition is available for all CMIS-compliant ECM systems such as Alfresco ECM, IBM FileNet P8, Nuxeo and EMC Documentum. Therefore, it provides a very cost-efficient but nevertheless fully professional way of managing and retrieving documents.

The Whole Platform is an open source technology for engineering the production of software. Based on the idea that programming is an activity concerning the development of domain languages, the Whole Platform provides an Eclipse-based Language Workbench

"RHQ (formerly Jopr), is an enterprise management solution for JBoss middleware projects and other application technologies. This pluggable project provides administration, monitoring, alerting, operational control and configuration in an enterprise setting with fine-grained security and an advanced extension model. Jopr is part of the multi-vendor RHQ management project. It provides support for monitoring base operating system information on six operating systems as well as mangement of Apache httpd, JBoss Application Server, Tomcat and other related projects."

"An "executable" UML model is one with a behavioral specification detailed enough that it can effectively be "run" as a program. This can be extremely valuable in order to test and validate the model, independently of the one or more implementation platforms to which the system being modeled will ultimately be deployed. Or, in some cases, the model itself can actually be run as the production implementation, given an appropriate execution environment. There have been model execution tools and environments for years, even before UML. However, each tool defined its own semantics for model execution, often including a proprietary action language, and models developed in one tool could not be interchanged with or interoperate with models developed in another tool. A previous post described Stephen Mellor's quest of more than a decade to change this through OMG standards for precise UML model execution semantics and a UML action language. In 2008, this led to the adoption of the Foundational UML (fUML) specification, providing the first precise operational and base semantics for a subset of UML encompassing most object-oriented and activity modeling. The fUML specification still did not provide any new concrete surface syntax, however, tying the precise semantics solely to the existing abstract syntax model of UML. This meant that, in order to fully specify a detailed behavior in a UML model - say the effect behavior of a transition on a state machine or the method of an operation of a class - one still had to draw a very detailed, graphical activity diagram. "

Welcome to the community home for Pentaho Data Integration Community Edition (PDI CE) also known as Kettle. Pentaho Data Integration delivers powerful Extraction, Transformation and Loading (ETL) capabilities using an innovative, metadata-driven approach. With an intuitive, graphical, drag and drop design environment, and a proven, scalable, standards-based architecture, Pentaho Data Integration is increasingly the choice for organizations over traditional, proprietary ETL or data integration tools. Community Edition is self supported open source software. An Enterprise Edition (EE) of Pentaho Data Integration including technical support, managed upgrades and enterprise features is also available. For more information about EE or for screenshots and datasheets, visit Pentaho Data Integration EE on Pentaho's corporate site.

Caching is the most important performance optimization technique. There are many things that can be cached in persistence, objects, data, database connections, database statements, query results, meta-data, relationships, to name a few. Caching in object persistence normally refers to the caching of objects or their data. Caching also influences object identity, that is that if you read an object, then read the same object again you should get the identical object back (same reference). JPA 1.0 does not define a shared object cache, JPA providers can support a shared object cache or not, however most do. Caching in JPA is required with-in a transaction or within an extended persistence context to preserve object identity, but JPA does not require that caching be supported across transactions or persistence contexts. JPA 2.0 defines the concept of a shared cache. The @Cacheable annotation or cacheable XML attribute can be used to enable or disable caching on a class.

Setting up an infrastructure for Instant Messaging" article series. In my previous tutorials, I showed you how to setup the Openfire IM Server and how to configure the Spark client in order to connect to that server. In this tutorial, I will show you how to add XMPP messaging capabilities to your own application. I will use the Smack library, an Open Source XMPP (Jabber) client library for instant messaging and presence. Smack is a pure Java library and can be embedded into your applications to create anything from a full XMPP client to simple XMPP integrations.

DdlUtils is a small, easy-to-use component for working with Database Definition (DDL) files. These are XML files that contain the definition of a database schema, e.g. tables and columns. These files can be fed into DdlUtils via its Ant task or programmatically in order to create the corresponding database or alter it so that it corresponds to the DDL. Likewise, DdlUtils can generate a DDL file for an existing database. DdlUtils uses the Turbine XML format, which is shared by Torque and OJB. This format expresses the database schema in a database-independent way by using JDBC datatypes instead of raw SQL datatypes which are inherently database specific. An example of such a file is:

"Businesses involve a lot of functions and in any company, large or small, dedicated departments handle the functions assigned to them. This compartmentalization ensures that experts in the respective domain handle things efficiently. But as the company grows there arises a situation when too much time and resources are wasted when each of the departments carry out functions that are redundant. For example, it is too expensive when both the purchase team and the warehouse management team maintain the same list of products but each in their own format. That may be a tiny part of how Enterprise Resource Planning (ERP) can help you avoid redundancies to run an efficient business. Based on the size of the company and requirements, ERP packages are available from a few thousand to millions of dollars. Today we'll check out how to set up Openbravo, a modern and professionally backed open source ERP that is cost effective to acquire, operate and upgrade."

"The goal of JavaMelody is to monitor Java or Java EE applications servers in QA and production environments. It is not a tool to simulate requests from users, it is a tool to measure and calculate statistics on real operation of an application depending on the usage of the application by users. JavaMelody is opensource (LGPL) and production ready: in production in an application of 25 person years. JavaMelody is easy to integrate in most applications and is lightweight (no profiling and no database). JavaMelody is mainly based on statistics of requests and on evolution charts. "

"OpenI is an open source Business Intelligence application for on-demand or SaaS deployments. Based on J2EE, OpenI is an out-of-box solution to easily visualize data from OLAP and relational databases, where users intuitively build and publish interactive reports, analyses, and dashboards."