Why?

[caffeine-mgn]

Version 4.12
Class com.cedarsoftware.util.io.ObjectResolver
Method: assignField
Line: 222

                else if (rhs instanceof String && "".equals(((String) rhs).trim()) && fieldType != String.class)
                {   // Allow "" to null out a non-String field
                    field.set(target, null);
                }

[caffeine-mgn]

I have some common result object like

data class Response(val result: Any? = null, val exception: Boolean = false)

And when my service returns empty string I got null