Java Reference
In-Depth Information
On an Apache web server, the server administrator can support JNLP by adding the fol-
lowing line to the server's
mime.types
(or
.mime.types
) file:
application/x-java-jnlp-file JNLP
If you can't get Java Web Start working on your server, you can test this project on the
book's official site. Load the web page
http://www.cadenhead.org/book/java-21days/java/
PageData.jnlp,
or visit the web address
http://www.java21days.com
and open the Day 14
page.
CAUTION
Java Web Start applications should look exactly like the applica-
tions do when run by other means. However, there appear to be a
few bugs in how much space is allocated to components on a
graphical user interface. On a Windows system, you might need to
add 50 pixels to the height of an application before employing it in
Java Web Start. Otherwise, the text fields are not tall enough to
display numbers.
Additional JNLP Elements
The JNLP format has other elements that can affect the performance of Java Web Start.
It can be used to change the title graphic that appears when the application is launched,
run signed applications that have different security privileges, run an application using
different versions of the Java interpreter, and other options.
Security
By default, all Java Web Start applications will not have access to some features of a
user's computer unless the user has given permission. This is similar to how the function-
ality of applets is limited.
If your application's JAR file has been digitally signed to verify its authenticity, it can be
run without these security restrictions by using the
security
element.
This element is placed inside the
jnlp
element, and it contains one element of its own:
all-permissions
. To remove security restrictions for an application, add this to a JNLP
file:
<security>
<all-permissions/>
</security>
