Refine ACME exception handling

- Simplify createBadNonceException() to accept a single detail string.
- Stop exception handling after sending an error when nonce creation fails.

Signed-off-by: andrew yuan <mingxuan199404@gmail.com>

Author: YuKiAndrew

base/acme/src/main/java/org/dogtagpki/acme/server/ACMEEngine.java

@@ -602,14 +602,14 @@ public void validateNonce(String value) throws Exception {
         }
 
         if (nonce == null) {
-            throw createBadNonceException("Invalid nonce: ",value);
+            throw createBadNonceException("Invalid nonce: " + value);
         }
 
         long currentTime = System.currentTimeMillis();
         long expirationTime = nonce.getExpirationTime().getTime();
 
         if (expirationTime <= currentTime) {
-            throw createBadNonceException("Expired nonce: ",value);
+            throw createBadNonceException("Expired nonce: "+ value);
         }
 
         logger.info("Valid nonce: " + value);
@@ -793,10 +793,10 @@ public Exception createMalformedException(String desc) {
         throw new ACMEException(HttpServletResponse.SC_BAD_REQUEST, error);
     }
 
-    public Exception createBadNonceException(String desc, String value) {
+    public Exception createBadNonceException(String detail) {
         ACMEError error = new ACMEError();
         error.setType("urn:ietf:params:acme:error:badNonce");
-        error.setDetail(desc + value);
+        error.setDetail(detail);
 
         throw new ACMEException(HttpServletResponse.SC_BAD_REQUEST,error);
     }

base/acme/src/main/java/org/dogtagpki/acme/server/ACMEServlet.java

@@ -57,6 +57,7 @@ protected void handlePKIException(
                 HttpServletResponse.SC_INTERNAL_SERVER_ERROR,
                 "Unable to generate replacement nonce"
             );
+            return;
         }
 
         super.handlePKIException(request, response, exception);