Error generating metadata when installing Shibboleth IdP v 4.0.1

[Rod Widdowson]

> BUILD FAILED
> /opt/shibboleth-identity-provider-4.0.1/bin/build.xml:20: java.lang.NullPointerException
>         at net.shibboleth.idp.installer.metadata.impl.MetadataGeneratorImpl.writeKeyDescriptors(MetadataGeneratorImpl.java:597)

I've never seen anything like this.  Were there any other errors further up?  

In general nothing should ever fail like this so you should put in a JIRA case.  You might want to turn up logging levels (either by
editing  install-log.xml or by pointing INSTALL_LOG_FILE to a suitable logback file.).

R