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"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. "

" A forum to dicuss about UML, MDA, MDD and all kinds of topics related to software modeling and model-driven engineering"

"The general architecture of Jackrabbit can be described in three Layers: A Content Application Layer, an API Layer and a Content Repository Implementation Layer."

Data, Context and Interaction (DCI) is a paradigm used in computer software to program systems of communicating objects. Its goals are: To improve the readability of object-oriented code by giving system behavior first-class status; To cleanly separate code for rapidly changing system behavior (what the system does) from code for slowly changing domain knowledge (what the system is), instead of combining both in one class interface; To help software developers reason about system-level state and behavior instead of only object state and behavior; To support an object style of thinking that is close to peoples' mental models, rather than the class style of thinking that overshadowed object thinking early in the history of object-oriented programming languages. The paradigm separates the domain model (Data) from Use cases (Context) and Roles that objects play (Interaction). DCI is complementary to Model-view-controller (MVC). MVC as a pattern language is still used to separate the data and its processing from presentation. DCI was invented by Trygve Reenskaug, also the inventor of MVC. The current formulation of DCI is mostly the work of Reenskaug and James O. Coplien.

"JCR v2.0 Specification (HTML version) Content Repository for Java Technology API Specification (JSR-283) "

"This page will be used to show solutions to common problems related to Apache Jackrabbit and the JCR API. These examples shouldn't be considered Best Practices - general error checking and exception handling have been omitted to keep the example code simple. "

This page contains the latest compiled builds of Pentaho Data Integration (Kettle) community edition.  The builds are based on source code downloaded daily from SVN. Why download these snapshot builds? You want the latest version - to get the latest features in PDI. You want a more stable version - PDI point releases (e.g. 4.0.1) can include important bug fixes - see the PDI JIRA system for a full list of known issues. You need a bug fixed - You're struggling with a critical bug which has been fixed in a more recent version. To save time - You haven't got the time and/or inclination to learn about how to download PDI from SVN and build your own version.

" Apache SlingTM is an innovative web framework that is intended to bring back the fun to web development. Discussions about Sling happen on our mailing lists, see the Project Information page for more info. Apache Sling in five bullets points REST based web framework Content-driven, using a JCR content repository Powered by OSGi Scripting inside, multiple languages (JSP, server-side javascript, Scala, etc.) Apache Open Source project"

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.

"The Frisbee module was developed as a "bag" of STK paragraphs with one common factor: social. These are the main features: CE / EE pure STK-based module drop-n-run module, with a self explaining demo website detailed instructions on module install one new Magnolia theme, frisbee, simple and clean Google Map (v3) integration . single marker map . multiple marker map, 2 demo marker-retrieval modelClass Flickr Slideshow, with custom query builder (tags, full-text search, author based search..) Facebook integration . Facebook SDK . Facebook iLike button . Facebook meta tag, reading values from page properties ShareThis and AddThis integration Twitter integration (you need Twitter4J.jar) . last tweet paragraph . last n tweets paragraphs . TweetThis button . ReTweet button Frisbee is at 1.0.0 stable version, but it is not ended here, it is open for future developments and integrations. Feel free to download it and to provide comments / contributions."

Each node in a Jackrabbit workspace tree has a node type that defines the child nodes and properties it may (or must) have. Developers can use node types to define a custom content model for their application domain and have Jackrabbit enforce the constraints of that model at the repository level.

The Java Content Repository (JCR) standard, which is based on the Java Specification Requests JSR170 (version 1.0) and JSR 283 (version 2.0), provides a Java-centric object-oriented storage API specifically targeted at content management scenarios. The JCR is not a content management system or a full-fledged content management system API, but rather a content repository API. A content repository provides a common API for all content-driven applications and CMS components, which require access to the content. It provides methods to read, write, and query content. The primary motivation of the JCR standard is to provide a standard and vendor-neutral programmatic interface for content repositories, allowing applications of multiple vendors to interact efficiently.

The previous sections have extensively used the CND notation to illustrate the examples. Now that the most important concepts have been demonstrated, this section will give an in-depth overview of the CND. JSR 283 further defines an XML-based format for defining node type definitions, however, it has not been finalized yet at the time of writing. A CND file contains a series of namespace declarations, node type definitions, as well as comments which are denoted with a double slash (//).

The Compact Namespace and Node Type Definition (CND) notation provides a compact standardized syntax for defining node types and making namespace declarations. The notation is intended both for documentation and for programmatically registering node types (if you are unfamiliar with JCR node types, you may want to read the general Node Types section first).

Singleton pattern is one of the most common patterns available and it's also used heavily in Java. This is also one of my favorite interview question and has lots of interesting follow-up to digg into details , this not only check the knowledge of design pattern but also check coding , multithreading aspect which is very important while working for a real life application.

JDBC realm has a lot of attention in recent months. This blog summarizes the evolution of the JDBC realm implementation in GlassFish and explains how the latest implementation works. I would like to thank Jean-Baptiste, and Richter for their contributions and comments. The participation from the open source community definitely helps everyone. I encourage all of you to give feedback, participate, and help evolve this feature further. GlassFish always had the capability for anyone to plug-in a realm. Implementing a custom realm in the Sun Java System Application Server EE 8.0 is described in the article Authentication Using Custom Realms in Sun Java System Application Server. In S1AS 7.x, there is a JDBC Realm bundled in sample. Jean-Baptiste formally filed an enhancement and provided a clear text version of JDBCRealm for GlassFish. Richter wrote another implementation because the GlassFish JDBCRealm at that time not compatible with Tomcat.

Apache Shiro (pronounced "shee-roh", the Japanese word for 'castle') is a powerful and easy-to-use Java security framework that performs authentication, authorization, cryptography, and session management and can be used to secure any application - from the command line applications, mobile applications to the largest web and enterprise applications. Shiro provides the application security API to perform the following aspects (I like to call these the 4 cornerstones of application security): Authentication - proving user identity, often called user 'login'. Authorization - access control Cryptography - protecting or hiding data from prying eyes Session Management - per-user time-sensitive state Shiro also supports some auxiliary features, such as web application security, unit testing, and multithreading support, but these exist to reinforce the above four primary concerns.

"Contributed and administered by ICEsoft Technologies Inc., ICEpdf.org is a place where enterprise Java developers can learn, share, and contribute information and ideas to a growing community of ICEpdf developers. ICEpdf is an open source Java PDF engine that can render, convert, or extract PDF content within any Java application or on a Web server. ICEpdf.org provides a range of development and support resources to benefit all ICEpdf developers. Source code and application reference implementations are available for download here. Numerous reference implementations and examples are available to enable rapid learning and successful use of the product. The reference implementations are commercial quality implementations that can be deployed as-is, customized to meet specific requirements, or used as learning aids on how to use various features. Visit the ICEpdf demos page to see ICEpdf in action and to evaluate the capabilities of ICEpdf as a Java PDF viewer or deployed as servlet a headless server engine. Remember that ICEpdf is completely customizable and and can be completely embedded in your Java application. We invite you to join the ICEpdf community and to participate in the user forums. The resources available here and on the ICEpdf forums will get you up and developing that much quicker. "

"Eclipse Plug-in for tailing log files and eclipse consoles (e.g. SVN, Java Stack Trace, CDT), including syntax coloring with either a regular expression or a word match. It allows you to have multiple logs open concurrently. "

"MultiTail lets you view one or multiple files like the original tail program. The difference is that it creates multiple windows on your console (with ncurses). It can also monitor wildcards: if another file matching the wildcard has a more recent modification date, it will automatically switch to that file. That way you can, for example, monitor a complete directory of files. Merging of 2 or even more logfiles is possible. It can also use colors while displaying the logfiles (through regular expressions), for faster recognition of what is important and what not. It can also filter lines (again with regular expressions). It has interactive menus for editing given regular expressions and deleting and adding windows. One can also have windows with the output of shell scripts and other software. When viewing the output of external software, MultiTail can mimic the functionality of tools like 'watch' and such."