Return empty unmodifiable set when no registered modules types. (#2374)

nstdio · cowtowncoder · commit a18e2c018891 · 2019-07-01T19:25:36.000-07:00
diff --git a/src/main/java/com/fasterxml/jackson/databind/ObjectMapper.java b/src/main/java/com/fasterxml/jackson/databind/ObjectMapper.java
@@ -988,9 +988,10 @@ public ObjectMapper registerModules(Iterable<? extends Module> modules)
      *
      * @since 2.9.6
      */
-    public Set<Object> getRegisteredModuleIds()
-    {
-        return Collections.unmodifiableSet(_registeredModuleTypes);
+    public Set<Object> getRegisteredModuleIds() {
+        return _registeredModuleTypes == null ?
+                Collections.emptySet() :
+                Collections.unmodifiableSet(_registeredModuleTypes);
     }
 
     /**

Original file line number	Diff line number	Diff line change
`@@ -988,9 +988,10 @@ public ObjectMapper registerModules(Iterable<? extends Module> modules)`
`988`	`988`	`*`
`989`	`989`	`* @since 2.9.6`
`990`	`990`	`*/`
`991`		`- public Set<Object> getRegisteredModuleIds()`
`992`		`- {`
`993`		`- return Collections.unmodifiableSet(_registeredModuleTypes);`
	`991`	`+ public Set<Object> getRegisteredModuleIds() {`
	`992`	`+ return _registeredModuleTypes == null ?`
	`993`	`+ Collections.emptySet() :`
	`994`	`+ Collections.unmodifiableSet(_registeredModuleTypes);`
`994`	`995`	`}`
`995`	`996`
`996`	`997`	`/**`