OPatch failed with error code 1:

CauseIssue:
=====
Opatch Fails with Exception in thread "main" java.lang.NoClassDefFoundError: # OPatch failed with error code 1:

Solution:
======

Applies to: 
Oracle Server - Enterprise Edition - Version 11.2.0.1 and later
Information in this document applies to any platform.

Symptoms

Opatch fails with errors:
$ORACLE_HOME/OPatch/opatch lsinventory
Exception in thread "main" java.lang.NoClassDefFoundError: #

OPatch failed with error code 1


Opatch reads oraparam.ini file for JRE memory options.
If oraparam.ini has commented lines like:
#JRE_MEMORY_OPTIONS=" -mx96m"
It gets the parameter as # -mx96m and raises the error Exception in thread "main" java.lang.NoClassDefFoundError: #

There is one bug 9698266 related to same issue though it is for different release.

Solution

Hence perform these steps:
1) Edit $ORACLE_HOME/oui/oraparam.ini
2) Remove commented lines for JRE_MEMORY_OPTIONS
3) execute opatch utility: opatch lsinventory to check if it works fine.

If still the error persists ,then there might be a case that oraparam.ini is corrupted.

Then need to replace this file with file available in other server (same database release and same platform) or from valid backup.

References
NOTE:314422.1 - Remote Diagnostic Agent (RDA) 4 - Getting Started
NOTE:732697.1 - What Information Oracle Support Need To Work On OPatch Service Requests?