I have an applet loaded via JNLP and running on jre 1.6.0_16 on IE7 or FF3.5 on Windows XP SP3 32bit.
In this applet. JNLP file specify all-permission, but I am unsure if this tag is relevant to applet or only to application. Anyway, it is in the jnlp file. This jnlp file is not signed.
Currently I am unsure about the SecurityManager that should control my applet. When I try to call File.createTempFile("aaaa", "bbb") in method init() ot start(), I get no problem at all: I create the file, I write to the file, I then delete it.
I am quite confident this is a bug, but I don't know what should be the correct behaviour.
So, it seems this is a known and expected behavior as discussed here: