Discoverer Plus 11g Through Load Balancer Or Proxy Fails: class oracle.disco.DiscoApplet not found (Doc ID 1363039.1)

Last updated on SEPTEMBER 27, 2016

Applies to:

Oracle Discoverer - Version 11.1.1.1.0 and later
Information in this document applies to any platform.
***Checked for relevance on 17-Jan-2014***

Symptoms

Accessing Discoverer Plus 11.1.1.x through a load balancer or proxy fails with error:

class oracle.disco.DiscoApplet not found.

Java Console error:

basic: load: class oracle.disco.DiscoApplet not found.
load: class oracle.disco.DiscoApplet not found.
java.lang.ClassNotFoundException: oracle.disco.DiscoApplet
at sun.plugin2.applet.Applet2ClassLoader.findClass(Unknown Source)
at sun.plugin2.applet.Plugin2ClassLoader.loadClass0(Unknown Source)
at sun.plugin2.applet.Plugin2ClassLoader.loadClass(Unknown Source)
at sun.plugin2.applet.Plugin2ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.plugin2.applet.Plugin2ClassLoader.loadCode(Unknown Source)
at sun.plugin2.applet.Plugin2Manager.createApplet(Unknown Source)
at sun.plugin2.applet.Plugin2Manager$AppletExecutionRunnable.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Exception: java.lang.ClassNotFoundException: oracle.disco.DiscoApplet
Ignored exception: java.lang.ClassNotFoundException: oracle.disco.DiscoApplet

Discoverer Viewer works fine.

Each of the standalone Discoverer nodes can be accessed directly successfully.

The problem occurs only when accessing Discoverer Plus through a load balancer / proxy, etc.

Changes

The problem has been observed when accessing Discoverer in SSL-mode through a BigIP/F5 Load Balancer, but may occur in other configurations as well.

Cause

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