String sep = props.getProperty("path.separator");

should be

String sep = SecurityActions.getSystemProperty("path.separator");

The passed in "props" is not the system property map in a managed domain, so this incorrect call will lead to an NPE

[Server:server-two] java.lang.NullPointerException
[Server:server-two] at java.util.regex.Pattern.quote(Pattern.java:1089)
[Server:server-two] at org.jboss.as.server.ServerEnvironment.getFilesFromProperty(ServerEnvironment.java:1018)
[Server:server-two] at org.jboss.as.server.ServerEnvironment.<init>(ServerEnvironment.java:320)
[Server:server-two] at org.jboss.as.server.ServerStartTask.run(ServerStartTask.java:117)
[Server:server-two] at org.jboss.as.server.DomainServerMain.main(DomainServerMain.java:129)
[Server:server-two] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
[Server:server-two] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:48)
[Server:server-two] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
[Server:server-two] at java.lang.reflect.Method.invoke(Method.java:600)
[Server:server-two] at org.jboss.modules.Module.run(Module.java:260)
[Server:server-two] at org.jboss.modules.Main.main(Main.java:291)