Java applet cached forever and not downloading new version?

Question

We have a case where clients seem to always cache applet versions. We use the <param name="cache_version"> correctly in our <object> , or we think so. We switched from the version line from 7.1.0.40 to 7.1.0.42 , and this caused a download for only half of our customers.

It doesn't seem to matter which version of the JRE is running on the client. We saw people face this problem on 1.4, 1.5, and 1.6.

Does anyone have experience using explicit cache versions? cache_archive it work more reliably (ignoring speed), instead relying on the cache_archive "Last-Modified" and / or "Content-Length" values ​​(according to the Sun site)?

FYI, the object block is as follows:

 <object> <param name="ARCHIVE" value="foo.jar"> <param name="CODE" value="com.foo.class"> <param name="CODEBASE" value="."> <param name="cache_archive" value="foo.jar"> <param name="cache_version" value="7.1.0.40"> <param name="NAME" value="FooApplet"> <param name="type" value="application/x-java-applet;jpi-version=1.4.2_13"> <param name="scriptable" value="true"> <param name="progressbar" value="true"/> <param name="boxmessage" value="Loading Web Worksheet Applet..."/> </object> 

Answer 1

Unfortunately, different versions of the Java Plug-In have different types of caching. Setting up cache controls and the latest modifications to HTTP headers is ideal, but it only works in the latest versions of the JRE.

The only solution guaranteed to work is to rename application banks when changing their versions (we observed strange caching behavior when trying to use other tricks, such as adding query strings based on file dates). This is not so difficult if you have a properly automated deployment system.

Answer 2

You can remove an applet from the Java cache using the Java Control Panel .
For example, in Win XP

 Start -> Control Panel -> Java -> Temporary Internet Files[View] 

Answer 3

According to this link , the same jar file should not be specified in the int parameters "archive" and "cache_archive". In this case, the JAR file is cached using its own browser cache.