failOnError is ignored if javadoc:javadoc is called via Site Plugin 3.0-beta

failOnError works for the case that javadoc:jar is executed. This invocation calls execute() and then generate(sink, locale). The generate is surrounded with a try/catch-block catching any exception thrown by the javadoc generation. In case of failOnError==false the exception does not interrupt the build. That perfectly ok!

failOnError does not work if it is called during site generation. During site generation only generate(sink, locale is called which misses the try/catch guard for failures during generation of javadoc.

Effectively you cannot ignore failures during site generation.