Index: oak-core/src/main/java/org/apache/jackrabbit/oak/plugins/nodetype/ReadOnlyNodeTypeManager.java
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
--- oak-core/src/main/java/org/apache/jackrabbit/oak/plugins/nodetype/ReadOnlyNodeTypeManager.java	(revision 1857255)
+++ oak-core/src/main/java/org/apache/jackrabbit/oak/plugins/nodetype/ReadOnlyNodeTypeManager.java	(date 1554908848000)
@@ -301,11 +301,15 @@
         return false;
     }
 
-    private static boolean isa(Tree types, String typeName, String superName) {
+    private static boolean isa(@Nullable Tree types, @NotNull String typeName, @NotNull String superName) {
         if (typeName.equals(superName)) {
             return true;
         }
 
+        if (types == null) {
+            return false;
+        }
+
         Tree type = types.getChild(typeName);
         if (!type.exists()) {
             return false;