ORA-00904: "GET_JAVA_PROPERTY": invalid identifier - 11gR2
Well, you found it somehow, didn't you?

It was never part of the database officially, it is just some custom function you can find on the Internet. For example: https://stackoverflow.com/questions/28164252/how-to-check-jdk-version-in-oracle

create function get_java_property(prop in varchar2)
return varchar2 is
language java name 'java.lang.System.getProperty(java.lang.String) return java.lang.String';