Google App Engine Deploy Fails: "Can't get the System Java Compiler"

Google App Engine Deploy Fails: "Can't get the System Java Compiler"

I have been deploying my app no trouble, then all of a sudden it fails. I
am not sure what I have done to cause this. The error messages when
deploying with the eclipse plugin were not very helpful. This info when
deploying from the commandline seems a little more informative:
Reading application configuration data...
Sep 27, 2013 5:48:50 PM
com.google.apphosting.utils.config.AppEngineWebXmlReader
readAppEngineWebXml
INFO: Successfully processed ./war\WEB-INF/appengine-web.xml
Sep 27, 2013 5:48:50 PM
com.google.apphosting.utils.config.AbstractConfigXmlRead
er readConfigXml
INFO: Successfully processed ./war\WEB-INF/web.xml
Sep 27, 2013 5:48:50 PM
com.google.apphosting.utils.config.AbstractConfigXmlRead
er readConfigXml
INFO: Successfully processed ./war\WEB-INF/queue.xml
Sep 27, 2013 5:48:50 PM
com.google.apphosting.utils.config.IndexesXmlReader read
ConfigXml
INFO: Successfully processed
.\war\WEB-INF\appengine-generated\datastore-indexes
-auto.xml
Beginning interaction for module default...
0% Created staging directory at:
'C:\Users\XXXXXX\AppData\Local\Temp\appcfg690
1219943971905638.tmp'
5% Scanning for jsp files.
8% Compiling jsp files.
Error Details:
Sep 27, 2013 5:50:39 PM org.apache.jasper.JspC processFile
INFO: Built File: \about.jsp
Sep 27, 2013 5:50:40 PM org.apache.jasper.JspC processFile
INFO: Built File: \admin.jsp
Then it spits out a whole bunch of lines for all the jsp files in the
project. After that it says:
java.lang.RuntimeException: Cannot get the System Java Compiler. Please
use a JD
K, not a JRE.
Unable to update app: Cannot get the System Java Compiler. Please use a
JDK, not
a JRE.
Please see the logs
[C:\Users\XXXXXXX\AppData\Local\Temp\appcfg6782250184385148
38.log] for further information.
This is what the error logs says:
Unable to update:
java.lang.RuntimeException: Cannot get the System Java Compiler. Please
use a JDK, not a JRE.
at
com.google.appengine.tools.admin.Application.compileJavaFiles(Application.java:814)
at
com.google.appengine.tools.admin.Application.compileJsps(Application.java:801)
at
com.google.appengine.tools.admin.Application.createStagingDirectory(Application.java:615)
at
com.google.appengine.tools.admin.AppAdminImpl.doUpdate(AppAdminImpl.java:418)
at
com.google.appengine.tools.admin.AppAdminImpl.update(AppAdminImpl.java:55)
at
com.google.appengine.tools.admin.AppCfg$UpdateAction.execute(AppCfg.java:1326)
at com.google.appengine.tools.admin.AppCfg.executeAction(AppCfg.java:327)
at com.google.appengine.tools.admin.AppCfg.<init>(AppCfg.java:210)
at com.google.appengine.tools.admin.AppCfg.<init>(AppCfg.java:121)
at com.google.appengine.tools.admin.AppCfg.main(AppCfg.java:117)
com.google.appengine.tools.admin.AdminException: Unable to update app:
Cannot get the System Java Compiler. Please use a JDK, not a JRE.
at
com.google.appengine.tools.admin.AppAdminImpl.doUpdate(AppAdminImpl.java:425)
at
com.google.appengine.tools.admin.AppAdminImpl.update(AppAdminImpl.java:55)
at
com.google.appengine.tools.admin.AppCfg$UpdateAction.execute(AppCfg.java:1326)
at com.google.appengine.tools.admin.AppCfg.executeAction(AppCfg.java:327)
at com.google.appengine.tools.admin.AppCfg.<init>(AppCfg.java:210)
at com.google.appengine.tools.admin.AppCfg.<init>(AppCfg.java:121)
at com.google.appengine.tools.admin.AppCfg.main(AppCfg.java:117)
Caused by: java.lang.RuntimeException: Cannot get the System Java
Compiler. Please use a JDK, not a JRE.
at
com.google.appengine.tools.admin.Application.compileJavaFiles(Application.java:814)
at
com.google.appengine.tools.admin.Application.compileJsps(Application.java:801)
at
com.google.appengine.tools.admin.Application.createStagingDirectory(Application.java:615)
at
com.google.appengine.tools.admin.AppAdminImpl.doUpdate(AppAdminImpl.java:418)
... 6 more