Echo1 FAQ

Getting Started

Q: How do I start using and learning Echo?
A: Visit the Echo Tutorial.

Software Requirements

Q: What are the server requirements to host an Echo-based application?
A: A Java Servlet Container implementing the Servlet 2.2 Specification is required to host an Echo-based application. The Java Virtual Machine must be compatible with JDK 1.2. (Sun 1.3 and 1.4 JDKs as well as the IBM 1.3 JDK are known to work).

Q: What browser platforms are supported by Echo?
A: Echo requires a Web browser that supports JavaScript version 1.3. Echo has been verified to work with Microsoft Internet Explorer 5.5 and 6.0, Mozilla 1.0, Opera 6.0, and Netscape 6.2. Echo also works with browsers that are based on these products.

Q: Why does Echo require client-side JavaScript?
A: In order to make Web applications behave like desktop applications, Echo needs to be able to control certain behaviors of the client browser. JavaScript provides a ubiquitously deployed means of accomplishing this. Echo's JavaScript has been tested in a wide variety of browsers under extreme conditions.


Q: How is Echo licensed?
A: Echo is licensed under the terms of the open-source GNU Lesser General Public License (LGPL). The terms of the LGPL license provide software developers with the ability to use the product royalty free to develop both open-source and closed-source (proprietary) applications. Developers may also modify the source code to the Echo framework itself, but in this case are required to submit their changes back to the community.

Q: Can proprietary applications be created using the Echo framework?
A: Yes, proprietary applications can be created using the Echo framework. Echo JAR files may be distributed with proprietary, closed-source applications. Echo is licensed under the GNU LGPL which does not impose any licensing requirements on applications that dynamically link to it. If you have any concerns over creating commercial software that uses LGPL libraries, please feel free to contact us.

Q: Can proprietary components be created and sold for the Echo framework?
A: Yes, proprietary components can be created and sold for the Echo framework. The LGPL does not impose any restrictions on the licensing of your product. The LGPL license requires that you publish source code only if you download and alter the source code of the Echo framework itself.


Q: What free support options are available?
A: Support for the Echo framework is freely available from the Echo development community. The best place to obtain free support is by joining the Echo Developer Forums and asking a question in the Help and Support forum.

A: Yes, NextApp provides commercial support for Echo.

Q: How do I report a bug?
A: Visit


Q: I encountered a server-side error in my application, what should I do?
A: When Echo encounters a server-side error, the client browser should issue a "JavaScript Alert" dialog indicating that an application error has occurred. This dialog will contain an error code, a number similar to this one: "34830f_1021586574083". Write down this error code (or at least the digits that precede the underscore) and then cross-reference it with an entry in your servlet container's log file. The record in the log file will indicate the exception that occurred and provide a stack trace, which will be useful in debugging your application. If you believe that the error is being caused by a problem within the Echo framework itself, see the support section.

Q: I encountered a JavaScript error while using an Echo application, what should I do?
A: First, understand that when Echo encounters a server-side error, it will display a JavaScript alert to the client browser. This alert dialog is not actually a JavaScript error. If you encounter this alert dialog, see the FAQ section titled "I encountered a server-side error in my application, what should I do?"

If the error you encountered is actually the result of flawed JavaScript code, please let us know by rporting it at Please include the platform type, browser version, and the operating system type and version. The more information we have on the problem the more successful we'll likely be at solving it.