javaee:string 

This is a special string datatype that is defined by Java EE as
a base type for defining collapsed strings. When schemas
require trailing/leading space elimination as well as
collapsing the existing whitespace, this base type may be
used.

Complex Type Information

Model

Attributes

QName Type Fixed Default Use Inheritable Annotation
id xsd:ID optional

Used By

Complex Types javaee:display-nameType, javaee:ejb-linkType, javaee:ejb-ref-typeType, javaee:env-entry-type-valuesType, javaee:fully-qualified-classType, javaee:generic-booleanType, javaee:java-identifierType, javaee:java-typeType, javaee:jndi-nameType, javaee:message-destination-linkType, javaee:message-destination-usageType, javaee:pathType, javaee:persistence-context-typeType, javaee:res-authType, javaee:res-sharing-scopeType, javaee:role-nameType
Elements javaee:facelet-taglib-functionType/javaee:function-name, javaee:facelet-taglib-functionType/javaee:function-signature, javaee:facelet-taglib-tag-behaviorType/javaee:behavior-id, javaee:facelet-taglib-tag-componentType/javaee:component-type, javaee:facelet-taglib-tag-componentType/javaee:renderer-type, javaee:facelet-taglib-tag-converterType/javaee:converter-id, javaee:facelet-taglib-tag-validatorType/javaee:validator-id, javaee:facelet-taglib-tagType/javaee:source, javaee:facelet-taglibType/javaee:namespace, javaee:message-destinationType/javaee:message-destination-name, javaee:param-valueType/javaee:param-name, javaee:persistence-context-refType/javaee:persistence-unit-name, javaee:persistence-unit-refType/javaee:persistence-unit-name, javaee:port-component-refType/javaee:port-component-link, javaee:service-ref_handlerType/javaee:handler-name, javaee:service-ref_handlerType/javaee:port-name, javaee:service-ref_handlerType/javaee:soap-role

Source 

<xsd:complexType name="string">
  <xsd:annotation>
    <xsd:documentation>This is a special string datatype that is defined by Java EE as a base type for defining collapsed strings. When schemas require trailing/leading space elimination as well as collapsing the existing whitespace, this base type may be used.</xsd:documentation>
  </xsd:annotation>
  <xsd:simpleContent>
    <xsd:extension base="xsd:token">
      <xsd:attribute name="id" type="xsd:ID"/>
    </xsd:extension>
  </xsd:simpleContent>
</xsd:complexType>