Question About JAR

Larry Helmerich (larryh@isocor.com)
Fri, 23 May 1997 11:15:11 -0700

Date: Fri, 23 May 1997 11:15:11 -0700
From: Larry Helmerich <larryh@isocor.com>
To: java-security@web2.javasoft.com
Subject: Question About JAR

I cannot seem to get jar archives to work. Must a jar archive be
signed. The documentation seems to indicate that jar is just an
archiver that may additionally sign classes. I am using jdk1.1.1 on a
Windows NT 4.0 system I have tried the following

javac con1.java
jar -cf con1.jar con1.class
-- security properites not found. using defaults
B.T.W my coworkers JDK1.1 system does not produce the above message

I then create an html file with the following tag
<applet code=con1.class archive="con1.jar" width=500 height=150>

I then remove the con1.class file from the directory. So the directory
contains the
html file and the jar file.

I then open the html file with Netscape Communicator 4.0 (which seems to
be able to deal with the Jar files found on javasoft's security page).
I get the following from the java console

# Applet exception: class con1 not found
java.lang.ClassNotFoundException: con1
Exception occurred while destroying applet:
java.lang.NullPointerException
Error in jar file: <unknown> error -1: internal error - couldn't
parse manifest file# Applet exception: class con1 not found
java.lang.ClassNotFoundException: con1

Note that I always get the message about not being able to parse the
manifest file, even when I down load the signed applet from
http://java.sun.com:80/security/examples/sign/
Which appears to deal with the Jar file correctly

What am I doing wrong, how do I get Jar files to work?