The JcrNodeTypeManager should not be dependent upon a JcrSession instance. Most of the methods (including those in JcrNodeType, JcrNodeDefinition, and JcrPropertyDefinition) only need an ExecutionContext. JcrNodeDefinition.getDefaultPrimaryType() seems to depend upon the NodeTypeManager to dynamically look up a type (there may be others). This main mean that the JcrNodeTypeManager needs a method to allow adding types from a JcrNodeTypeSource (rather than a JcrNodeTypeSource be passed into the constructor).