使用XSD文件验证XML格式时报异常

Exception---------------------------------
Exception in thread "main" java.lang.StackOverflowError
at java.lang.Character.toLowerCase(Character.java:4175)
at java.lang.String.toLowerCase(String.java:2409)
at java.lang.String.toLowerCase(String.java:2497)
at org.apache.xerces.util.URI.setScheme(URI.java:908)
at org.apache.xerces.util.URI.initializeScheme(URI.java:576)
at org.apache.xerces.util.URI.initialize(URI.java:400)
at org.apache.xerces.util.URI.<init>(URI.java:211)
at org.apache.xerces.util.URI.<init>(URI.java:195)
at org.apache.xerces.impl.XMLEntityManager.expandSystemId(XMLEntityManager.java:1140)
at org.apache.xerces.impl.XMLEntityManager.resolveEntity(XMLEntityManager.java:581)
at org.apache.xerces.impl.xs.XMLSchemaLoader.xsdToXMLInputSource(XMLSchemaLoader.java:625)
at org.apache.xerces.impl.xs.XMLSchemaLoader.processJAXPSchemaSource(XMLSchemaLoader.java:580)
at org.apache.xerces.impl.xs.XMLSchemaLoader.loadSchema(XMLSchemaLoader.java:489)

conf.xsd---------------------------------
<?xml version="1.0"?>   
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"   
           targetNamespace="http://www.w3school.com.cn"   
           xmlns="http://www.w3school.com.cn"   
           elementFormDefault="qualified"> 

    <xs:element name="students">   
        <xs:complexType>   
            <xs:sequence>   
            <xs:element name="student" maxOccurs="5">
            <xs:complexType>
            <xs:sequence>
            <xs:element name="id" type="xs:string" />
            <xs:element name="name" type="xs:string" />
            </xs:sequence>
            </xs:complexType>
            </xs:element>
            </xs:sequence>   
        </xs:complexType>   
    </xs:element>   
</xs:schema>

conf.xml-------------------------------------
<?xml version="1.0"?>
<students xmlns="http://www.w3school.com.cn" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.w3school.com.cn file:///">
<student>
<id>dsf</id>
<name>sdf</name>
</student>
</students>