From: Tom Mueller <tom.mueller_at_oracle.com>
Date: Mon, 28 Nov 2011 07:53:45 -0600

It appears that you are compiling with JDK 1.7 but are running GlassFish
with JDK 1.6.
In the NetBeans project properties dialog, under the "Sources" category,
there is a drop-down menu that allows you to select the version of Java
for your sources and binaries. If you are running GlassFish with 1.6,
then this should be set to 1.6 for any applications that you deploy to
the server.

Tom