Nexaweb Launcher

Nexaweb Launcher is based on an open source project (GetDown).  It is a solution that Nexaweb  provides in responses to the announcement of  Oracle that it is going to obsolete WebStart technology. 

Nexweb  Launcher includes three parts: 

1. nexaweblauncher.exe  is a shell program that when it is invoked by the file association, it first checks through the system to locate an existing installed JRE, and uses it to launch getdown-1.7.1-SNAPSHOT.jar
2. getdown-1.7.1-SNAPSHOT.jar  is an jar that interprets a nexaweb file and then launches Nexaweb web application from the web server.
3. The file with extension nexaweb , it is the instruction list that tells how to properly launch Nexaweb web application

On the client side, the work flow is almost same as JNLP, except that the customer needs to install Nexaweb launcher on their client machines so that nexaweb launcher is able to associates it with the file extension nexaweb and for that it can launch itself when the user double clicks the file with an extension nexaweb and its work flows is as below:

1. First, The users download the file with extension nexaweb froman URL: http://< your host>:<your port>/<your application>/runNexaweb   serviced by runNexaweb.jsp and save it
2. Next, they double click nexaweb 
3. As the computer opens nexaweb file, it invokes nexaweblauncher.exe which is associated with nexaweb file type
4. nexaweblauncher.exe  interprets the file and generates an instruction list including  downloading the jars, resources file,  digest files, comparing the digest files to see if it needs to download the files or just use the cached files, etc., all which it needs to bring a Nexaweb web application alive
5. And then, it executes the instructions and launches the nexaweb web  application
6. After the nexaweb web application has been launched, it exits. 

On the server side, NexawebImages.jar and NexawebStandaloneClient.jar need to be added into WebContent directory just like with jnlp. If the nexaweb web application is dependent on some other jars, those jars too must be added into WebContent directory.

Nexaweb launcher uses Getdown’s digester to generate jar’s digest and use the digest to check if it needs to download a new version jar file or not. So the users need to digest all jars the web application needed and put them in the same directory with GetDown.txt which is just the same file run.nexaweb in a different name. After generating the digest files, they need to be added into WebContent directory too as the jars.