Name: pa48320 Date: 12/18/2001

Optional packages should not install in same directory as JRE standard
extensions.

Prior to 1.4, Javasoft did not ship any standard extensions in
jre/lib/ext. In 1.4, the JRE comes with:

    dnsns.jar
    jgss_kerberos.jar
    ldapsec.jar
    sunjce_provider.jar

However, Optional Packages installed by applets also install jar files
in this same directory. This makes it impossible for a Java application
to ensure a consistent, clean deployment run time environment. Prior to
1.4, we could run Java applications with

   java -Djava.ext.dirs= com.sas.myapp.Main

and this insulate the application from any jars downloaded by applets
using the Optional Package specification. If we launch 1.4-based
applications using this runtime option, these new jars will not be
available.

Optional Package jars downloaded by applets will also cause a
performance problem for non-applet applications which use the same JRE.
For example, when an application loads a resource such as a class or
resource bundle, the application classloader will first delegate to the
extension class loader (which in turn delegates to tbe boot class
loader). The extension class loader will then try to find that resource
in all the optional package jars.

To fix this, java.ext.dirs should be two separate directories

    jre/lib/standard-ext

         would contain dnsns.jar, jgss_kerberos.jar, ldapsec.jar,
         sunjce_provider.jar, and other jar files Javasoft
         or JVM vendors wish to ship with their JRE.
         
    jre/lib/optional-packages

         would contain jars downloaded by the applet Optional Package
         specification.
         
Further, the extension directory path used by the Java tools (java,
javadoc, javap, javaws, web servers, etc.) would be

    -Djava.ext.dirs=JAVA_HOME/jre/lib/standard-ext

and the java.ext.dirs used by the plug in would be

    -Djava.ext.dirs=JAVA_HOME/jre/lib/standard-ext;JAVA_HOME/jre/lib/optional-packages;

Thus, applications could run in a clean environment, not polluted by
applet Optional Package installed jars.

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