How to get the children/links of a workitem (e.g. PCR) with Java Plain API?

I have a workitem (PCR type) which finded by ID. Now I want to get a list which contains all of the children workitems (Task type) of this PCR. After that I want to get the status of the Tasks and push them to another function. PCR has more links not just the Tasks!
How is it possible to get the list/array of Tasks?
Thanks your help!
One answer

See: https://rsjazz.wordpress.com/2012/09/19/the-rtc-workitem-link-api-linking-workitems-to-other-elements/
Also: https://rsjazz.wordpress.com/2012/09/20/the-rtc-workitem-server-link-api-linking-to-work-items-and-other-elements/
https://rsjazz.wordpress.com/2015/09/30/learning-to-fly-getting-started-with-the-rtc-java-apis/
You can search that blog for other items