fix npe on AbstractKapuaConfigurableResourceLimitedService if maxNumb…

…erChildEntities not present

Signed-off-by: riccardomodanese <riccardo.modanese@eurotech.com>

commons/src/main/java/org/eclipse/kapua/commons/configuration/AbstractKapuaConfigurableResourceLimitedService.java

@@ -128,8 +128,11 @@ protected int allowedChildEntities(KapuaId scopeId, KapuaId targetScopeId, Map<S
                 long childCount = 0;
                 for (Account childAccount : childAccounts.getItems()) {
                     Map<String, Object> childConfigValues = getConfigValues(childAccount);
-                    int maxChildChildAccounts = (int) childConfigValues.get("maxNumberChildEntities");
-                    childCount += maxChildChildAccounts;
+                    // maxNumberChildEntites can be null if such property is disabled via the
+                    // isPropertyEnabled() method in the service implementation. In such case,
+                    // it makes sense to treat the service as it had 0 available entities
+                    Integer maxNumberChildEntities = (Integer) childConfigValues.get("maxNumberChildEntities");
+                    childCount += maxNumberChildEntities != null ? maxNumberChildEntities : 0;
                 }
 
                 // Max allowed for this account