There is no such thing as JBoss AS 7.5 community edition. Where did you find reference to that?
Sorry for making mistake. I just assume that JBoss EAP 6.4 should be based on JBoss AS 7.5...
Can you tell me what the latest version of JBoss AS 7 is and where can I find the complete source code for compilation purpose? Thanks.
Reading your question again, it appears that you want to build the EAP 6.4 from source. If that's the case, then you can find the EAP source for download here ftp://ftp.redhat.com/redhat/jbeap/.
As to how to build that source, I haven't tried it myself, but there have been previous discussions about it, like here: