//Athenticate and join to group
AuthenticationCredential authCred = new AuthenticationCredential(group,null,creds);
MembershipService membership = group.getMembershipService();
Authenticator auth = membership.apply(authCred);
if(auth.isReadyForJoin()){
Credential myCred = membership.join(auth);
printOnLog("[===== Detalhes do Grupo =====]");
StructuredTextDocument doc = (StructuredTextDocument)myCred.getDocument(new MimeMediaType("text/plain"));
StringWriter out = new StringWriter();
doc.sendToWriter(out);
printOnLog(out.toString());
printOnLog("[+]Nome do PEER: " + group.getPeerName() + " está online:-)\n");