How to get a nested field

Question

I'm new of reflection and I'm trying to get a nested field. Summarizing I have the following classes:

public class Agreement{

    private Long id;

    private String cdAgreement;

    private Address address;

    //Constructor getter and setter

}

public class Address{

    private Long id;

    private String description;

    //Constructor getter and setter

}

Now I want to get the description field, then i wrote this code:

Agreement agreement = new Agreement();
Class c = agreement.getClass();
Field f = c.getDeclaredField("address.descritpion");

but not works, I get the following exception:

java.lang.NoSuchFieldException: address.descritpion
at java.lang.Class.getDeclaredField(Class.java:1948)

Where am I doing wrong?

Answer 1

The current problem is that no field has the name "address.description" (it's not even a valid name for a field).

You have to get the address field first, access its class, and get the nested field from there. To do so, use getType():

Agreement agreement = new Agreement();
Class c = agreement.getClass();          // Agreement class
Field f = c.getDeclaredField("address"); // address field
Class<?> fieldClass = f.getType();       // class of address field (Address)
Field nested = fieldClass.getDeclaredField("description"); // description field

You can also chain the calls without local variables:

Field nested = c.getDeclaredField("address").getType().getDeclaredField("description");