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Many interactive Web applications are composed of brittle collections of interdependent Web pages. Such applications can be hard to maintain and extend. The Front Controller pattern defines a single component that is responsible for processing application requests. A front controller centralizes functions such as view selection, security, and templating, and applies them consistently across all pages or views. Consequently, when the behavior of these functions need to change, only a small part of the application needs to be changed: the controller and its helper classes.

Many interactive Web applications are composed of brittle collections of interdependent Web pages. Such applications can be hard to maintain and extend. The Front Controller pattern defines a single component that is responsible for processing application requests. A front controller centralizes functions such as view selection, security, and templating, and applies them consistently across all pages or views. Consequently, when the behavior of these functions need to change, only a small part of the application needs to be changed: the controller and its helper classes.

By applying the Model-View-Controller (MVC) architecture to a JavaTM 2 Platform, Enterprise Edition (J2EETM) application, you separate core business model functionality from the presentation and control logic that uses this functionality. Such separation allows multiple views to share the same enterprise data model, which makes supporting multiple clients easier to implement, test, and maintain.

Java BluePrints Model-View-Controller

Database Change Management You never develop code without version control, why do you develop your database without it? Liquibase is an open source (Apache 2.0 Licensed), database-independent library for tracking, managing and applying database changes. It is built on a simple premise: All database changes are stored in a human readable yet trackable form and checked into source control. Liquibase Supports: Extensibility Merging changes from multiple developers Code branches Multiple Databases Managing production data as well as various test datasets Cluster-safe database upgrades Automated updates or generation of SQL scripts that can be approved and applied by a DBA Update rollbacks Database "diff"s Generating starting change logs from existing database

"Since 1994, the Java programming language evolved and became a valid tool to develop reliable and performant server applications as opposed to just applets and client applications. The major disadvantage of the Java platform is that still today the only portable way to start a Java application relies on a single point of entry: the public static void main(String[]) method. Having a single-point of entry is a valid solution for client applications, where interactively a user can command to the application to quit (which can terminate the Virtual Machine process at calling the System.exit(int) method), but in those cases where the application is not interactive (server applications) there is currently no portable way to notify the Virtual Machine of its imminent shutdown. A server application written in Java might have to perform several tasks before being able to shutdown the Virtual Machine process. For example in the case of a Servlet container, before the VM process is shut down, sessions might need to be serialized to disk, and web applications need to be destroyed. One common solution to this problem is to create (for example) a ServerSocket and wait for a particular message to be issued. When the message is received, all operations required to shut down the server applications are performed and at the end the System.exit method is called to terminate the Virtual Machine process. This method however, has several disadvantages and risks: In case of a system-wide shutdown, the Virtual Machine process may be shut down directly by the operating system without notifying the running server application. If an attacker finds out the shutdown message to send to the server and discovers a way to send this message, he can easily interrupt the server's operation, bypassing all the security restrictions implemented in the operating system. Most multi-user operating systems already have a way in which server applications are started and stopped. Under Unix based

Core Java Topics - Overview Of Programming With Java, Datatypes, Variables, Operators, Control Statements, Methods - Importance, Array - Overview, Classes, Class Inheritance, Methods Overiding and Overloading, Abstract Class And Methods, Interfaces, Packages and Access Control, final, static and others, Object Oriented Concepts - Revisited, Exceptions, Generics, Strings, Exploring java.lang, Collections Framework, More Utility Classes, Input/Output: Exploring java.io, Other Core Java Topics

If you control the code, you control the world.

Java supports two selection statements - if and switch. These statements allow us to control the flow of the program. Depending upon the expressions or values, the corresponding blocks/statements of code will be executed or by passed. The two statements are if statement is a conditional branch statement. This is a two way branch statement. Depending upon the whether a condition is true or false, the corresponding code is executed. switch statement is a multiway branch statement. Depending upon the value used for switching, the corresponding code is executed. These two statements are very powerful and are used widely across any application. They provide effective solutions for branching problems.

Sample tutorial on how of Spring Dependency Injection and Inversion of Control using Constructor Injection and Setter Injection

A tutorial on how to create a web application using basic Spring MVC from spring-framework 3.0.5. We will design our web-based application based on the standard Spring MVC where request to the web-app will be routed to a Controller module, then to it's jsp View with data from our business Model

"Sonatype Nexus: Manage Artifacts Sonatype Nexus sets the standard for repository management providing development teams with the ability to proxy remote repositories and share software artifacts. Download Nexus and gain control over open source consumption and internal collaboration."

With AutoPatch, an agile development process that requires a database change looks like this: Developer alters the model, which requires a change to the database Developer possibly consults a DBA, and develops a SQL patch against their personal database that implements the alteration Developer commits the patch to source control at the same time as they commit their dependent code Other developers' and environments' databases are automatically updated by AutoPatch the next time the new source is run This represents streamlined environment maintenance, allowing developers to cheaply have their own databases and all databases to stay in synch with massively lower costs and no environment skew. That's what AutoPatch does. Clusters with one database? Multiple schemas? Logical migrations, instead of just DDL changes? Need to do something special/custom? Need to distribute your changes commercially? All without paying anything? No problem.

Squill is a slick internal DSL for writing SQL queries in pure Java. It uses the database metadata and generics to catch as many errors as possible during compilation and is almost completely typesafe. At the same time it is designed to allow everything SQL allows you to do, exactly the way SQL is meant to do it. This means that you're encouraged to select only the data you need and no hidden queries are generated for you, leaving you in full control of the query performance. Squill also supports database-specific extensions, allowing you to both use advanced features and fully tweak your queries.

Spring Security is a powerful and highly customizable authentication and access-control framework. It is the de-facto standard for securing Spring-based applications Spring Security is one of the most mature and widely used Spring projects. Founded in 2003 and actively maintained by SpringSource since, today it is used to secure numerous demanding environments including government agencies, military applications and central banks. It is released under an Apache 2.0 license so you can confidently use it in your projects. Spring Security is also easy to learn, deploy and manage. Our dedicated security namespace provides directives for most common operations, allowing complete application security in just a few lines of XML. We also offer complete tooling integration in SpringSource Tool Suite, plus our Spring Roo rapid application development framework. The Spring Community Forum and SpringSource offer a variety of free and paid support services. Spring Security is also integrated with many other Spring technologies, including Spring Web Flow, Spring Web Services, SpringSource Enterprise, SpringSource Application Management Suite and SpringSource tc Server.

Atmosphere is a POJO based framework using Inversion of Control (IoC) to bring push/Comet and Websocket to the masses! Finally a framework which can run on any Java based Web Server, including Tomcat, Jetty, GlassFish, Weblogic, Grizzly, JBossWeb and JBoss, Resin, etc. without having to learn how Comet or WebSocket support has been differently implemented by all those Containers. The Atmosphere Framework has both client (JQuery PlugIn) and server components. Servlet 3.0 is supported along with framework like Jersey (natively), GWT (natively), Wicket, Guice, Spring etc. and programming language like JRuby, Gr oovy and Scala. We also support massive scalability with our Cluster plugin architecture (JGroups, JMS/ActiveMQ, Redis, XMPP,i etc.)

HttpClient Cache provides an HTTP/1.1-compliant caching layer to be used with HttpClient--the Java equivalent of a browser cache. The implementation follows the Decorator design pattern, where the CachingHttpClient class is a drop-in replacement for a DefaultHttpClient; requests that can be satisfied entirely from the cache will not result in actual origin requests. Stale cache entries are automatically validated with the origin where possible, using conditional GETs and the If-Modified-Since and/or If-None-Match request headers. HTTP/1.1 caching in general is designed to be semantically transparent; that is, a cache should not change the meaning of the request-response exchange between client and server. As such, it should be safe to drop a CachingHttpClient into an existing compliant client-server relationship. Although the caching module is part of the client from an HTTP protocol point of view, the implementation aims to be compatible with the requirements placed on a transparent caching proxy. Finally, CachingHttpClient includes support the Cache-Control extensions specified by RFC 5861 (stale-if-error and stale-while-revalidate).

I think many people have the same feeling (of course including me)