What is Java Web Start and how is it launched?

The Java Web Start software allows you to download and run Java applications from the web. The Java Web Start (JWS) software:

  • Provides an easy, one-click activation of applications
  • Guarantees that you are always running the latest version of the application
  • Eliminates complicated installation or upgrade procedures
To start the client, just click on the "Launch" button on the main page. Java will download the program and automatically conduct a number of security checks, e.g. the permissions the program is asking for and the signature used to sign the program. PEE Mail asks for full access to your system, because otherwise you would not be able to select files for attachments, store your mails on disk or to use security for encryption. A Java Web Start will never start without your explicit permission. At first start, you'll most likely see a dialogue like the following:
JWS requesting permission to run a program
JWS requesting permission to run a program
If you want to verify the author of a Java Web Start program, click on the details link. This allows you to go through a number of dialogues and to check the certificate of a program's author:
Displaying Certificate Details
Displaying Certificate Details
Click OK if you are happy with what you see and if you trust the author. In case of PEE Mail it is possible that the security request pops up twice. Some systems don't ask for permission just for the main program but also for the libraries it is using. I think, it is a bit annoying but of course security has to come first! If everything is OK and you gave sufficient permissions, the application will start and you can use it.