ClassLoader opening a network connection?

[Obiwan2u]

I'm setting up the Java environment on my Win 98 PC and the first time I tried
to run a "Hello World" application (while not connected to the internet), I got
an error which makes me paranoid:

C:\Ben\Java>java HelloWorldApp
Exception in thread "main" java.lang.ClassFormatError: Unknown constant tag in
.
class file
at sun.net.www.protocol.file.Handler.openConnection(Unknown Source)
at java.net.URL.openConnection(Unknown Source)
at java.net.URLClassLoader.getPermissions(Unknown Source)
at sun.misc.Launcher$AppClassLoader.getPermissions(Unknown Source)
at java.security.SecureClassLoader.getProtectionDomain(Unknown Source)
at java.security.SecureClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.access$100(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClassInternal(Unknown Source)

Why the heck is my ClassLoader trying to open a network connection? Is this
some new national security initiative?

Note, I connected to the internet and reran the exact same thing, and it ran
fine.

I have a software firewall called ZoneAlarm running on the PC, and it usually
prompts me for the first time a new binary program tries to access the
internet. It did not prompt/warn me when I successfully ran the class file
the 2nd time. So maybe a network connection was not opened. But then what the
heck is the above error about?

So my question is, is my ClassLoader informing on me? (not that there's much
to inform about)

Oh yeah, I got the Java environment from a CD that came with the book "The Java
Tutorial, 3rd Edition". The version info for the ClassLoader is:

java version "1.3.0"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.3.0-C)
Java HotSpot(TM) Client VM (build 1.3.0-C, mixed mode)

Ben