Address PR Comments

Author: jencymaryjoseph

.changes/next-release/bugfix-UrlConnectionClient-4dd3b0c.json

@@ -2,5 +2,5 @@
     "type": "bugfix",
     "category": "Url Connection Client",
     "contributor": "",
-    "description": "Handle unhandled NullPointerException wrapped in RuntimeException when underlying connection fails with URL Connection HTTP Client"
+    "description": "Wrap NullPointerException wrapped in RuntimeException as IOException to allow retry when underlying connection fails with URL Connection HTTP Client"
 }

http-clients/url-connection-client/src/main/java/software/amazon/awssdk/http/urlconnection/UrlConnectionHttpClient.java

@@ -368,7 +368,7 @@ private <T> Optional<T> getAndHandle100Bug(Supplier<T> supplier, boolean failOn1
             } catch (RuntimeException e) {
                 if (e.getCause() instanceof NullPointerException) {
                     throw new UncheckedIOException(new IOException(
-                        "Unexpected RuntimeException wrapping NullPointerException from HttpURLConnection", e));
+                        "Unexpected NullPointerException when calling HttpURLConnection", e));
                 }
 
                 if (!exceptionCausedBy100HandlingBug(e)) {
@@ -438,8 +438,8 @@ private static int getResponseCodeSafely(HttpURLConnection connection) throws IO
                 throw new IOException("Unexpected NullPointerException when trying to read response from HttpURLConnection", e);
             } catch (RuntimeException e) {
                 if (e.getCause() instanceof NullPointerException) {
-                    throw new IOException("Unexpected RuntimeException wrapping NullPointerException when trying to "
-                                          + "read response from HttpURLConnection", e);
+                    throw new IOException("Unexpected NullPointerException when trying to read response from "
+                                          + "HttpURLConnection", e);
                 }
                 throw e;
             }