diff --git a/jpa/eclipselink.jpa.test/src/it/java/org/eclipse/persistence/testing/tests/jpa/advanced/PersistenceUnitProcessorTest.java b/jpa/eclipselink.jpa.test/src/it/java/org/eclipse/persistence/testing/tests/jpa/advanced/PersistenceUnitProcessorTest.java
index a1fe896..dea8248 100644
--- a/jpa/eclipselink.jpa.test/src/it/java/org/eclipse/persistence/testing/tests/jpa/advanced/PersistenceUnitProcessorTest.java
+++ b/jpa/eclipselink.jpa.test/src/it/java/org/eclipse/persistence/testing/tests/jpa/advanced/PersistenceUnitProcessorTest.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015, 2020 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2015, 2022 Oracle and/or its affiliates. All rights reserved.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v. 2.0 which is available at
@@ -79,6 +79,21 @@
         );
     }
 
+    private static void checkPURootCustomWithCustomDescriptorLocation(
+            String inputScheme,
+            String inputFile,
+            String expectedOutput,
+            String descriptorLocation
+    ) throws Exception {
+        assertEquals(
+                expectedOutput,
+                PersistenceUnitProcessor.computePURootURL(
+                        new URL(inputScheme, "", -1, inputFile, dummyHandler),
+                        descriptorLocation
+                ).toString()
+        );
+    }
+
     private static void checkPURootFailsCustom(
         String inputScheme,
         String inputFile
@@ -119,6 +134,15 @@
             "jar:file:/foo/bar.war!/WEB-INF/classes/"
         );
 
+        // WAR files have a special location available.
+        // Simulate event when custom persistence descriptor file name is used and specified e.g.
+        // System.setProperty(PersistenceUnitProperties.ECLIPSELINK_PERSISTENCE_XML, "WEB-INF/classes/META-INF/my-persistence.xml");
+        checkPURootCustomWithCustomDescriptorLocation(
+                "zip", "/foo/bar.war!/WEB-INF/classes/META-INF/my-persistence.xml",
+                "file:/foo/bar.war",
+                "WEB-INF/classes/META-INF/my-persistence.xml"
+        );
+
         // Same as the previous one, but not a WAR!
         checkPURootFailsCustom(
             "zip", "/foo/bar.jar!/WEB-INF/classes/META-INF/persistence.xml"
diff --git a/jpa/org.eclipse.persistence.jpa/src/main/java/org/eclipse/persistence/internal/jpa/deployment/PersistenceUnitProcessor.java b/jpa/org.eclipse.persistence.jpa/src/main/java/org/eclipse/persistence/internal/jpa/deployment/PersistenceUnitProcessor.java
index d21d9c0..fb12a85 100644
--- a/jpa/org.eclipse.persistence.jpa/src/main/java/org/eclipse/persistence/internal/jpa/deployment/PersistenceUnitProcessor.java
+++ b/jpa/org.eclipse.persistence.jpa/src/main/java/org/eclipse/persistence/internal/jpa/deployment/PersistenceUnitProcessor.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1998, 2021 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1998, 2022 Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 1998, 2018 IBM Corporation. All rights reserved.
  *
  * This program and the accompanying materials are made available under the
@@ -753,7 +753,7 @@
             // archive, and file is the URL of that archive. Since
             // the innermost archive has to be a JAR (according to JPA Spec),
             // this case is handled by the previous branch.
-            return rootEntry.equals(WEBINF_CLASSES_STR);
+            return rootEntry.equals(WEBINF_CLASSES_STR) || rootEntry.isEmpty();
         } else {
             return false;
         }