Fix NPE in RetryPolicy.hashCode() (#2672)

Author: dagnir

.changes/next-release/bugfix-AWSSDKforJavav2-f2c1771.json

@@ -0,0 +1,6 @@
+{
+    "category": "AWS SDK for Java v2", 
+    "contributor": "", 
+    "type": "bugfix", 
+    "description": "Fix `NullPointerException` in `RetryPolicy.hashCode()`."
+}

core/sdk-core/src/main/java/software/amazon/awssdk/core/retry/RetryPolicy.java

@@ -234,7 +234,7 @@ public int hashCode() {
         result = 31 * result + Boolean.hashCode(additionalRetryConditionsAllowed);
         result = 31 * result + backoffStrategy.hashCode();
         result = 31 * result + throttlingBackoffStrategy.hashCode();
-        result = 31 * result + Boolean.hashCode(fastFailRateLimiting);
+        result = 31 * result + Objects.hashCode(fastFailRateLimiting);
         return result;
     }
 

core/sdk-core/src/test/java/software/amazon/awssdk/core/retry/RetryPolicyTest.java

@@ -180,4 +180,9 @@ public void fastFailRateLimitingConfigured_retryModeNotAdaptive_throws() {
     public void fastFailRateLimitingConfigured_retryModeAdaptive_doesNotThrow() {
         RetryPolicy.builder(RetryMode.ADAPTIVE).fastFailRateLimiting(true).build();
     }
+
+    @Test
+    public void hashCodeDoesNotThrow() {
+        RetryPolicy.defaultRetryPolicy().hashCode();
+    }
 }