A month ago I hit Bug 13902704 “SRVM.JAR IS LOCKED BY OPATCH 11.2.0.3.0” while trying to apply Patch 3 (Patch# 13570057) on top of 11.2.0.3 (Windows 7 x64 & 2008 R2). With Sysinternals Procmonitor (better than Process Explorer for tracing file usage) I soon found out that opatch 11.2.0.3 itself is locking out of the game install process.
Opatch greeted me with the error shown in the screenshot’s:

Ok, I said to myself, I’ll wait for Patch 4 (13783453), someone at Oracle will certainly notice such an apparent bug. It didn’t happen and I’m not surprised anymore. It’s not that nobody outside of the Oracle Corp. patches Oracle kernel, it’s more likely no one from Oracle Corp. is testing patch installation anymore. At least not in live.
Anyway, according to support note 1446273.1 the workaround for the bug is simple file rename before and after opatch apply:

cmd> move %ORACLE_HOME%\OPatch\jlib\oracle.opatch.classpath.jar %ORACLE_HOME%\OPatch\jlib\oracle.opatch.classpath1.jar
cmd> opatch apply
cmd> move %ORACLE_HOME%\OPatch\jlib\oracle.opatch.classpath1.jar %ORACLE_HOME%\OPatch\jlib\oracle.opatch.classpath.jar

Bug will be fixed in the next opatch release.