Hi,
I found on a Sun page that you can determine in a JSP if Java Web Start is present on the client machine.
I have an Applet that requires Java 1.5 or higher and I'm trying to determine if Java is present in the browser (if not, I'll redirect to a "download now" page). If Java Web Start is present can I assume that Java 1.5 is also?
Thanks, slegge
...
> I found on a Sun page
Sun has lots of pages. Care to narrow it
down by supplying an URL to that page?
>..that you can determine in a JSP
> if Java Web Start is present on the client machine.
I doubt it. There are various scripts determined
to ascertain if JNLP content type is recognised
by the browser, but just because it is, does not
mean that Java is actually currently installed,
enabled and of suitable minimum version for
an app.
> I have an Applet ..
Do you want to run the applet using JWS, or web start?
There are pretty straightforward solutions to ensuring
an applet in a browser has a particular mimimum
version of Java available in the browser.
OTOH - web start has its own mechanism for
ensuring a suitable JRE is available.
>..that requires Java 1.5 or higher and
> I'm trying to determine if Java is present in the
> browser (if not, I'll redirect to a "download now"
> page).
That is not very relevant. I can be running
three separate browsers, NN 4.78 with
Symantec 1.1.5 Java, IE showing both the
MSVM in one instance, while running Sun
1.6 in another instance, and FireFox running
yet another Java version (though more
probably the late model Sun Java version).
>..If Java Web Start is present can I assume
> that Java 1.5 is also?
No.
Detect if the browser understands web start,
then spcify a minimum version of Java and a
download URL in the JNLP file.
The user will either
- get the app. on-screen, running suitable Java.
- Be prompted to download install the Java version,
before seeing the project on-screen.
- Be informed it requires 'x.x' Java, and it could not
be auto-downloaded (*nix/Mac. OS).
There is a tehcnique can be used from a web
start app. to communicate back to an (for example)
'launch applet' that, assuming the app. has not
'reported in' after a suitable time, assumes the
launch failed, and changes to another page.
> Sun has lots of pages. Care to narrow it down by supplying an URL to that page?
This is the page I was referring to:
http://java.sun.com/j2se/1.5.0/docs/guide/javaws/developersguide/contents.html
Specifically, "Detecting if JavaWeb Start is installed on IE, and if so, the version"
> Do you want to run the applet using JWS, or web start?
The Applet is in the web page.I don't want the user to have to install it on their machine. Of course, I need Java 1.5 to be enabled in the browser, so there's my problem.
> There are pretty straightforward solutions to ensuring an applet in a browser has a particular mimimum version of Java available in the browser.
Sound like that's what I need. How do I do that?
> Detect if the browser understands web start, then spcify a minimum version