Fix deprected usage if 'newInstance'

[sschulz92]

Within the javadoc of newInstance() it is described how to fix the deprecation (Class.class):

clazz.newInstance() can be replaced by clazz.getDeclaredConstructor().newInstance()

This is what I did for all places where this deprecation occured.

[sschulz92]

@fgdrf do you mind having a look onto this beauty? :)