Problem using App Engine on Mac Java JRE

I really appreciate the help i've been getting on Stack Overflow, it's helping me become a better programmer. Im currently learning how to use the Google App Engine, and ive just developed my first app, but im finding it difficult to run. When i run it, it throws the following exceptions:

WARNING: Use on a JRE prior to version 1.6 is deprecated
2011-06-04 12:19:21.190 java[1921:80f] [Java CocoaComponent compatibility mode]: Enabled
2011-06-04 12:19:21.191 java[1921:80f] [Java CocoaComponent compatibility mode]: Setting timeout for SWT to 0.100000
Initializing AppEngine server
   [WARN] ********************开发者_如何学运维************************************
Warning: Future versions of the Dev App Server will require Java 1.6 or later. Please upgrade your JRE.
********************************************************

Logging to JettyLogger(null) via com.google.apphosting.utils.jetty.JettyLogger
Successfully processed /Users/josiahuma/Projects/Eclipse/JWorkspace/HelloWorld/war/WEB-INF/appengine-web.xml
Successfully processed /Users/josiahuma/Projects/Eclipse/JWorkspace/HelloWorld/war/WEB-INF/web.xml

Ive tried looking for ways to download and install JRE 1.6 or maybe upgrade it like the error say, but haven't found any on MAC... Please can anyone help put me through on what exactly i need to do so i can get my first app running. Would really appreciate it.

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Upgrade to 10.6. The default JVM is Java 6 there.