cannot write to property without a setter

[Reuben Firmin]

Let's say I have a class structure as per below. Ibatis doesl not seem to let 
me address the path foo.bah.someProperty, because there is no setter 
(Foo#setBah). Specifically, I get "com.ibatis.common.beans.ProbeException: 
There is no WRITEABLE property". Spring, on the other hand, is fine with this 
particular setup, and in fact seems to ignore the setBah() method if it exists. 
Is there a good argument for one way or the other? 

public class Foo 
{
    private Bah bah;

    public Foo()
    {
        bah = new Bah();
    }

    public Bah getBah()
    {
        return bah;
    }
}

public class Bah
{
    private int someProperty;
 
    public int getSomeProperty()
    ...

    public void setSomeProperty(int someProperty)
    ...
}