Java XML against XSD: The prefix "xs" for element "xs:schema" is not bound

Question

I have trouble with my validation and I can't find any solutions. I am validating an XML file against this. XSD with my own Java 9 program which throws an Exception with the error message

The prefix "xs" for element "xs:schema" is not bound.

<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
<xs:element name="vDiPE">
    <xs:complexType>
            <xs:sequence>
                    <xs:element name="itemIn"/>
                    <xs:element name="itemCo"/>
                    <xs:element name="exitcon" cid="xs:integer" />
                    <xs:element name="condition">
                            <xs:complexType>
                                    <xs:sequenece>
                                            <xs:element name="if" />
                                            <xs:element name="then" />
                                    </xs:sequence>
                                    <xs:attribute name="id" type="xs:integer" use="required"/>
                            </xs:complexType>
                    </xs:element>
                    <xs:element name="">
            </xs:sequence>
            <xs:attribute name="id" type="xs:integer" use="required" />
            <xs:attribute name="texPath" type="xs:string" use="required" />
            <xs:attribute name="name" type="xs:string" default="Unnamed Item" />
            <xs:attribute name="positionX" type="xs:integer" use="required" />
            <xs:attribute name="positionY" type="xs:integer" use="required" />

            <xs:attribute name="draw" type="xs:boolean" default="true" />
            <xs:attribute name="hitbox" type="xs:boolean" default="false" />
            <xs:attribute name="collidable" type="xs:boolean" default="false" />

            <xs:attribute name="hintgiving" type="xs:boolean" default="false" />

            <xs:attribute name="used" type="xs:boolean" default="false" />
    </xs:complexType>

What is wrong? I researched a much but nothing fixed the issue :(