(node:9436) [DEP0018] DeprecationWarning:

BUILD FAILED in 2m 41s
Picked up _JAVA_OPTIONS: -Xmx512M
(node:9436) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

How is that related to Ionic Pro?

It is also only the non-relevant part of a bigger error message.
What is your ionic info output?