The XMLSchema defines that whitespaces should be collapsed for type names and different attribute values that can contain type names. JAXB internal schema parser (XSOM) does not support this functionality. And it can cause failures in wsimport tool. WSDL file with such types definition section (space in 'type' attribute value):
  <wsdl:types>
    <xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"
      targetNamespace="http://www.temp.com/Service/">
      <xsd:element name="HelloRequest" type="xsd:string"/>
      <xsd:element name="HelloResponse" type="xsd:string"/>
          <xsd:complexType name="info">
                  <xsd:sequence>
                        <xsd:element name="firstname" type="xsd:string"/>
                        <xsd:element name="lastname" type="xsd:string"/>
                  </xsd:sequence>
          </xsd:complexType>
                  
          <xsd:complexType name="usage">
                  <xsd:all>
                        <xsd:element name="customerCharacteristics" type="hy:info "/>
                  </xsd:all>
          </xsd:complexType>
    </xsd:schema>
  </wsdl:types>

Causing the following wsimport failure:
parsing WSDL...


[ERROR] undefined simple or complex type 'hy:info '
  line 25 of file:/home/aefimov/Oracle/BUGS/JAX-WS_B/23559210_wsimport_spaces/sampleservice.wsdl.xml

Exception in thread "main" com.sun.tools.internal.ws.wscompile.AbortException
at com.sun.tools.internal.ws.processor.modeler.wsdl.JAXBModelBuilder.bind(JAXBModelBuilder.java:129)
at com.sun.tools.internal.ws.processor.modeler.wsdl.WSDLModeler.buildJAXBModel(WSDLModeler.java:2283)
at com.sun.tools.internal.ws.processor.modeler.wsdl.WSDLModeler.internalBuildModel(WSDLModeler.java:183)
at com.sun.tools.internal.ws.processor.modeler.wsdl.WSDLModeler.buildModel(WSDLModeler.java:126)
at com.sun.tools.internal.ws.wscompile.WsimportTool.buildWsdlModel(WsimportTool.java:429)
at com.sun.tools.internal.ws.wscompile.WsimportTool.run(WsimportTool.java:190)
at com.sun.tools.internal.ws.wscompile.WsimportTool.run(WsimportTool.java:168)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at com.sun.tools.internal.ws.Invoker.invoke(Invoker.java:159)
at com.sun.tools.internal.ws.WsImport.main(WsImport.java:42)

XSOM parser should be modified to collapse whitespaces in type names in respect to XMLSchema types definitions (https://www.w3.org/2001/XMLSchema.xsd)