In TCK 1.1.20, we were able to close and re-create an instance of ComponentManager.
Since 1.1.21 and https://github.com/Talend/component-runtime/commit/b2ddf1eb6e9b69d314d72ba8a566c303d790b7b1#diff-01ce0e085c5c637b311151aeea014292d01ab73b8795b2d693d78cef3a9b8877, it seems that once a component manager has been closed, it can't be re-created anymore.
ComponentManager m1 = ComponentManager.instance();
m1.close();
ComponentManager m2 = ComponentManager.instance();
// m2 is null