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Editorial Team
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Asked: 2026-06-04T11:00:23+00:00

Using seam-gen based code. I have an object Classroom, which contains an instance of

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Using seam-gen based code. I have an object “Classroom”, which contains an instance of “Location”. I want to query for classrooms but specifying a value on the Location object.

Something like ‘select from Classroom where Location.State = “NY”‘. When I try to bind a selectOneMenu with a list of states to #{ClassroomList.classroom.location.state} I’m getting errors.

Was getting a null pointer exception on Location. I’m assuming I need to instantiate a new “Location” on the Classroom object, but not sure where to do that. On the Classroom entity’s constructor? On the ClassroomList backing bean (where the example object is bound to the ClassroomList JSP search fields)?

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  1. Editorial Team

    Not sure if this is the best way, but I got it working.

    I have a String exposed on my ClassroomList backing bean as “String locationState”. My dropdown list of states binds to that

    Then that’s referenced in my restrictions as:
    …
    lower(classroom.location.state) like lower(concat(#{classroomList.locationState}, ‘%’))”,
    …

    —

    When I tried to instantiate ClassroomList.instance.Location, I would get:
    javax.servlet.ServletException with message: “Id and clazz must not be null”
    Not sure what’s causing that?

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