Pyjnius - How does autocomplete suggestions work for return types of methods?

[Madhawa Vidanapathirana]

Hi,

When I use Pyjnius in PyCharm Console, I get autocomplete suggestions. 

e.g.
String = autoclass("java.lang.String")
s = String("Hello")
And if I type s., I get autocomplete suggestions for String type. 
Furthermore, if I type s.getClass()., I get autocomplete suggestions for class type.

1) How does pyjnius inform this information to autocomplete? 

2) Is there any technique for myself to programmatically receive these autocomplete suggestions?

I am more interested to know how this works for return types of methods (as suggestions come before I execute the method)

Thanks in advance,

Madhawa