I got an error deploying the EARs. Now every time I try to start JBOSS, I get this error EXCEPTION_ACCESS_VIOLATION. For this reason, I am stuck and cannot initialize the database to continue installing AEM forms.
With turnkey installer we have Java 1.8 update 74, you can try that. You should use pre-configured Jboss. Go through supportability matrix as well 
OS is Windows Server 2012 R2
we are not using the turnkey installation because we are setting up a cluster configuration for JBOSS application server and using SQL server for the database.
What OS are you using? Is this a JBoss turnkey install, if so the installer will install everything it needs. If not what appserver and DB are you using?
AEM forms is supposed to work with Java 8, we already have the latest version of JDK installed. Do you have a version that will work?
Issue seems to be with JVM. Check,. If you are using non-turnkey installer try to update Java.