How to interpret Zero-Length XML Element Content?

Question

Given an element with zero-length content <foo></foo> , is the textual value of foo "" or null ?

Does the answer depend on whether the containing document is being interpreted by some schema or other?

Answer 1

It is considered an empty string. There is no concept of "null" in XML. There is a "nil", which is specified as an attribute like:

<foo xsi:nil="true" />

There is also the option of simply omitting the element, which may be considered "null-like" to the consumer of the XML.

For example, JAXB marshals both "nil" and a missing element to a Java null , and you can configure how it behaves in the reverse scenario.