Refactoring of sending HTTP 500 in ContainerMapper

- previous version had too wide try-catch blocks where in one of deployment_all
  test cases one exception caused another which was preventable.
- this version logs just the original exception and then a message if it cannot
  send the http 500 or another exception if it tried and it failed, but no NPE.

Signed-off-by: David Matějček <david.matejcek@omnifish.ee>

nucleus/core/kernel/src/main/java/com/sun/enterprise/v3/services/impl/ContainerMapper.java

@@ -46,6 +46,8 @@
 import org.glassfish.internal.grizzly.ContextMapper;
 import org.glassfish.kernel.KernelLoggerInfo;
 
+import static java.util.logging.Level.WARNING;
+
 /**
  * Container's mapper which maps {@link ByteBuffer} bytes representation to an  {@link HttpHandler}, {@link
  * ApplicationContainer} and ProtocolFilter chain. The mapping result is stored inside {@link MappingData} which
@@ -140,31 +142,42 @@ protected void configureMapper() {
     public void service(final Request request, final Response response) throws Exception {
         try {
             request.addAfterServiceListener(afterServiceListener);
-
-            final Callable handler = lookupHandler(request, response);
-            handler.call();
+            lookupHandler(request, response).call();
         } catch (Exception ex) {
-            try {
-                if (LOGGER.isLoggable(Level.WARNING)) {
-                    final Object url = request.getRequest() == null ? null
-                        : request.getRequest().getRequestURIRef().getDecodedRequestURIBC();
-                    LogHelper.log(LOGGER, Level.WARNING, KernelLoggerInfo.exceptionMapper, ex, url);
-                }
+            logAndSendError(request, response, ex);
+        }
+    }
 
-                response.sendError(500);
-            } catch (Exception ex2) {
-                LOGGER.log(Level.WARNING, KernelLoggerInfo.exceptionMapper2, ex2);
-                if (ex2 instanceof CharConversionException) {
-                    response.sendError(500);
-                }
-            }
+    private void logAndSendError(final Request request, final Response response, Exception ex) {
+        if (LOGGER.isLoggable(WARNING)) {
+            final Object url = toUrlForLogging(request);
+            LogHelper.log(LOGGER, WARNING, KernelLoggerInfo.exceptionMapper, ex, url);
+        }
+        if (response.getResponse() == null) {
+            LOGGER.log(WARNING, "Response is not set in {0}, there's nothing we can do now.", response);
+            return;
+        }
+        try {
+            response.sendError(500);
+        } catch (Exception ex2) {
+            LOGGER.log(WARNING, KernelLoggerInfo.exceptionMapper2, ex2);
+        }
+    }
+
+
+    private Object toUrlForLogging(final Request request) {
+        try {
+            return request.getRequest() == null ? null : request.getRequest().getRequestURIRef().getDecodedRequestURIBC();
+        } catch (CharConversionException e) {
+            return null;
         }
     }
 
-    private Callable lookupHandler(final Request request,
-            final Response response) throws CharConversionException, Exception {
-        MappingData mappingData;
 
+    private Callable lookupHandler(final Request request, final Response response)
+        throws CharConversionException, Exception {
+
+        MappingData mappingData;
         mapperLock.readLock().lock();
 
         try {