Displaying Employee (HR schema) records in Hierarchical Tree can be achieved in ADF-BC by creating custom VO and a Viewlink for displaying root node. This can be more easily done using  EJB-DC by just introducing a NamedQuery to get the root node.

Here you go to get this scenario working.

• Create DB connection based on HR schema.
  
• Create Entity Bean from Employees Table.
• Add custom NamedQuery to Employees.java bean, this named query is responsible for fetching the root node (King in this example).

@NamedQueries({
  @NamedQuery(name = "Employees.findAll", query = "select o from Employees o"),
  @NamedQuery(name = "Employees.findRootEmp", query = "select p from Employees p where p.employees is null")
})

• Create Stateless Session Bean and expose the Named Queries through the Session Facade.

• Create Datacontrol from SessionBean local interface.

• Create jspx page in ViewController project.
• Drop employeesFindRootEmp from Data Controls Palette as ADF Tree.

• Add employeesList as Tree level rule.

• Run page to see the hierarchical tree with root node as 'King'