Fix null not accepted on PDP message

Issue-ID: POLICY-1648
Change-Id: I580d1c433cd3a5730b115ef6353770f17939cf3a
Signed-off-by: liamfallon <liam.fallon@est.tech>
diff --git a/models-pdp/src/main/java/org/onap/policy/models/pdp/persistence/concepts/JpaPdp.java b/models-pdp/src/main/java/org/onap/policy/models/pdp/persistence/concepts/JpaPdp.java
index 6276418..528d6fb 100644
--- a/models-pdp/src/main/java/org/onap/policy/models/pdp/persistence/concepts/JpaPdp.java
+++ b/models-pdp/src/main/java/org/onap/policy/models/pdp/persistence/concepts/JpaPdp.java
@@ -193,7 +193,7 @@
                     "PDP health status may not be null"));
         }
 
-        if (StringUtils.isBlank(message)) {
+        if (message != null && StringUtils.isBlank(message)) {
             result.addValidationMessage(new PfValidationMessage(key, this.getClass(), ValidationResult.INVALID,
                     "message may not be blank"));
         }
diff --git a/models-pdp/src/test/java/org/onap/policy/models/pdp/persistence/concepts/JpaPdpTest.java b/models-pdp/src/test/java/org/onap/policy/models/pdp/persistence/concepts/JpaPdpTest.java
index 5a27210..ebdf31c 100644
--- a/models-pdp/src/test/java/org/onap/policy/models/pdp/persistence/concepts/JpaPdpTest.java
+++ b/models-pdp/src/test/java/org/onap/policy/models/pdp/persistence/concepts/JpaPdpTest.java
@@ -149,6 +149,8 @@
         testJpaPdp.setKey(savedKey);
         assertTrue(testJpaPdp.validate(new PfValidationResult()).isOk());
 
+        testJpaPdp.setMessage(null);
+        assertTrue(testJpaPdp.validate(new PfValidationResult()).isOk());
         testJpaPdp.setMessage("");
         assertFalse(testJpaPdp.validate(new PfValidationResult()).isOk());
         testJpaPdp.setMessage("Valid Message");