Question

Is this the appropriate way to access bean properties of an Object without knowing/caring about its exact type? (Or is there a built-in method that does this already?) Is there an appropriate exception to throw when a property does not exist or is not available?

static private Object getBeanPropertyValue(Object bean, String propertyName) {
    // access a no-arg method through reflection
    // following bean naming conventions
    try {
        Method m = bean.getClass().getMethod(
                "get"
                +propertyName.substring(0,1).toUpperCase()
                +propertyName.substring(1)
                , null);
        return m.invoke(bean);
    }
    catch (SecurityException e) {
        // (gulp) -- swallow exception and move on
    }
    catch (NoSuchMethodException e) {
        // (gulp) -- swallow exception and move on
    }
    catch (IllegalArgumentException e) {
        // (gulp) -- swallow exception and move on
    }
    catch (IllegalAccessException e) {
        // (gulp) -- swallow exception and move on
    }
    catch (InvocationTargetException e) {
        // (gulp) -- swallow exception and move on
    }
    return null; // it would be better to throw an exception, wouldn't it?
}

Answer 1

If you can’t use Commons BeanUtils, you can get there with jre classes

java.beans.Introspector

BeanInfo beanInfo = Introspector.getBeanInfo(bean.getClass());
PropertyDescriptor[] descriptors = beanInfo.getPropertyDescriptors();
for(PropertyDescriptor pd : descriptors)
{
    if(pd.getName().equals(propertyName)
    {
        return pd.getReadMethod().invoke(bean, (Object[])null);
    }
}