Be careful because the validator is not thread safe.
It is the responsibility of the application to make the code thread safe.
It does not have any value to speak of (no name), but it is still precisely defined.
So a namespace that does have a name can never be used as the default namespace.
If the XSD is publicly available using HTTP and referenced through a "schema Location" or "no Namespace Schema Location", then the validator will pick it up and it doesn't need to be specified/uploaded.
*The maximum size limit for file upload is 2 megabytes.
These are the same constants you define when using XML Schema for SAX parsing, and they are declared at the beginning of the Because JAXP-compliant parsers are not namespace-aware by default, it is necessary to set the property for schema validation to work.
You are seeing it here, because at this point you have learned enough about namespaces for the discussion to make sense.
declaration consists of entry pairs, where the first entry in each pair is a fully qualified URI that specifies the namespace, and the second entry contains a full path or a relative path to the schema definition. In that way, only one copy of the schema will tend to exist.
Note that you cannot use the namespace prefixes when defining the schema locations.
To contrive an example, consider an XML data set that keeps track of personnel data.
The data set may include information from a tax declaration form as well as information from the employee's hiring form, with both elements named Note - The default namespace is actually a specific namespace.