Maybe this answers some of your questions Higher memory consumption in Java 8 than Java 7 - Stack Overflow
So one of the reasons can be that Java requires more memory because it moved to Metaspace model.
But as you can see in screenshots in JBoss 7 there are 529 Modules instances which has size 30MB but in Wildfly there are 577 Modules which has size 390MB
I am not sure understanding your issue. Higher versions usually mean (fortunately) more functionality and (unfortunately) higher requirements to your environment (disk space, memory, cpu aso). But nowadays this should not be a big cost factor anymore.
Out of curiosity - are you comparing the same module in those screenshots (where you show the allPaths member)? If so, is that module shipped out of the box by the server and what's the name of that module? Furthermore, do you see the same pattern for all other modules that are shipped or just a few of these?
1. I comparing the same module (by identifier) .
2. This are my modules app.ear#customer.jar. In ear I have about 500 modules like this. subldeployment-isolation=false
2. Each my module (in ear) has allPaths with size over 13.000 which is strange... these paths contains packages I think.
This is the same app from JBoss 7 from which I had to remove old log4j, java-ee.api, some webservice spec...those libs conflicts with WIldfly libs...and thats all. No any changes. Of course I understand that new stack can require more resources but this looks like bug. + 300 MB is not a problem but + 50s startup time in dev mode is a nightmare
I've now tried to reproduce your issue. I've used jboss-as-7.1.1.Final with jdk1.7.0_80 and wildfly-10.1.0.Final with jdk1.8.0_121. I deployed just one application (Oracle Application Listener
ords.188.8.131.528.07.16 with the same i.war and ords.war).
But the figures did not deviate dramatically. I'd therefore assume that this relates to your application. Maybe you embedded some modules in your ear which are not needed anymore in WildFly