function getPageClassList has incorrect return type

function getPageClassList from class ConfigService
has an incorrect signature

public List<? extends Page> getPageClassList();

while it should be

public List<Class<? extends Page>> getPageClassList();

This function when used causes sometimes ClassCastException. However this is not repeatable. I assume that javac compiler generates code which try to cast to incorrect generic type.
Loop construction like
for(Class<? extends Page> clazz : configService.getPageClassList())

is rejected by java compiler

Please correct the signature in ConfigService and its implementation in XmlConfigService