xml - How to fix the error: cvc-elt.1: Cannot find the declaration of element 'xsd:schema' without namespaces?

Question

I'm using input.xsd schema file:

<?xml version="1.0" encoding="UTF-8"?>
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema">

    <xsd:element name="Mobiles">
        <xsd:complexType>
            <xsd:sequence>
                <xsd:element name="Mobile" type="Mobile" maxOccurs="unbounded"/>
            </xsd:sequence>
        </xsd:complexType>
    </xsd:element>

    <xsd:complexType name="Mobile">
        <xsd:sequence>
            <xsd:element name="Model" type="xsd:string"/>
            <xsd:element name="OS">
                <xsd:simpleType>
                    <xsd:restriction base="xsd:string">
                        <xsd:enumeration value="Android"/>
                    </xsd:restriction>
                </xsd:simpleType>
            </xsd:element>
            <xsd:element name="Origin" type="xsd:string"/>
            <xsd:element name="Material" type="xsd:string"/>
            <xsd:element name="Samsung" type="Samsung"/>
        </xsd:sequence>
    </xsd:complexType>

    <xsd:complexType name="Samsung" mixed="true">
        <xsd:sequence>
            <xsd:element name="Wlan">
                <xsd:simpleType>
                    <xsd:restriction base="xsd:string">
                        <xsd:enumeration value="802.11"/>
                    </xsd:restriction>
                </xsd:simpleType>
            </xsd:element>
            <xsd:element name="CardSlot" type="xsd:string"/>
            <xsd:element name="RadioAvailability" type="xsd:boolean" default="true"/>
            <xsd:element name="BluetoothAvailability" type="xsd:boolean" default="false"/>
        </xsd:sequence>
    </xsd:complexType>
</xsd:schema>

And input.xml file looks like:

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<Mobiles
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:noNamespaceSchemaLocation="input.xsd">
    <Mobile>
        <Model>G975F</Model>
        <OS>Android</OS>
        <Origin>USA</Origin>
        <Material>Plastic</Material>
        <Samsung>
            <Wlan>802.11</Wlan>
            <CardSlot>MicroSD</CardSlot>
            <RadioAvailability>true</RadioAvailability>
            <BluetoothAvailability>true</BluetoothAvailability>
        </Samsung>
    </Mobile>
    <Mobile>
        <Model>G986</Model>
        <OS>Android</OS>
        <Origin>USA-Israel</Origin>
        <Material>Silicon-Plastic</Material>
        <Samsung>
            <Wlan>802.11</Wlan>
            <CardSlot>MicroSD</CardSlot>
            <RadioAvailability>true</RadioAvailability>
            <BluetoothAvailability>false</BluetoothAvailability>
        </Samsung>
    </Mobile>
    <Mobile>
        <Model>G770F</Model>
        <OS>Android</OS>
        <Origin>Israel</Origin>
        <Material>Silicon-Plastic</Material>
        <Samsung>
            <Wlan>802.11</Wlan>
            <CardSlot>MicroSD</CardSlot>
            <RadioAvailability>true</RadioAvailability>
            <BluetoothAvailability>false</BluetoothAvailability>
        </Samsung>
    </Mobile>
</Mobiles>

I've followed this answer as example without namespaces for schema and this for better theoretical understanding.

But I'm always getting the issue locally in console when I'm trying to validate xsd schema file:

cvc-elt.1: Cannot find the declaration of element 'xsd:schema'.
org.xml.sax.SAXParseException; systemId: file:///F:/IdeaProject/TestProject/input.xsd; lineNumber: 2; columnNumber: 58; cvc-elt.1: Cannot find the declaration of element 'xsd:schema'.
    at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.createSAXParseException(ErrorHandlerWrapper.java:203)
    at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.error(ErrorHandlerWrapper.java:134)
    at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:396)
    at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:327)
    at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:284)
    at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator.handleStartElement(XMLSchemaValidator.java:1901)
    at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator.startElement(XMLSchemaValidator.java:741)
    at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.scanStartElement(XMLNSDocumentScannerImpl.java:374)
    at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl$NSContentDriver.scanRootElementHook(XMLNSDocumentScannerImpl.java:613)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:3132)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$PrologDriver.next(XMLDocumentScannerImpl.java:852)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:602)
    at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.next(XMLNSDocumentScannerImpl.java:112)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:505)
    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:842)
    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:771)
    at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:141)
    at com.sun.org.apache.xerces.internal.parsers.DOMParser.parse(DOMParser.java:243)
    at com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:339)
    at javax.xml.parsers.DocumentBuilder.parse(DocumentBuilder.java:177)
    at com.epam.rd.java.basic.practice7.controller.DOMController.parse(DOMController.java:96)
    at com.epam.rd.java.basic.practice7.controller.DOMController.main(DOMController.java:331)
    at com.epam.rd.java.basic.practice7.DOMControllerTest.main(DOMControllerTest.java:11)
    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 org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecutor.runTestClass(JUnitTestClassExecutor.java:110)
    at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecutor.execute(JUnitTestClassExecutor.java:58)
    at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecutor.execute(JUnitTestClassExecutor.java:38)
    at org.gradle.api.internal.tasks.testing.junit.AbstractJUnitTestClassProcessor.processTestClass(AbstractJUnitTestClassProcessor.java:62)
    at org.gradle.api.internal.tasks.testing.SuiteTestClassProcessor.processTestClass(SuiteTestClassProcessor.java:51)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:36)
    at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)
    at org.gradle.internal.dispatch.ContextClassLoaderDispatch.dispatch(ContextClassLoaderDispatch.java:33)
    at org.gradle.internal.dispatch.ProxyDispatchAdapter$DispatchingInvocationHandler.invoke(ProxyDispatchAdapter.java:94)
    at com.sun.proxy.$Proxy2.processTestClass(Unknown Source)
    at org.gradle.api.internal.tasks.testing.worker.TestWorker.processTestClass(TestWorker.java:118)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:36)
    at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)
    at org.gradle.internal.remote.internal.hub.MessageHubBackedObjectConnection$DispatchWrapper.dispatch(MessageHubBackedObjectConnection.java:182)
    at org.gradle.internal.remote.internal.hub.MessageHubBackedObjectConnection$DispatchWrapper.dispatch(MessageHubBackedObjectConnection.java:164)
    at org.gradle.internal.remote.internal.hub.MessageHub$Handler.run(MessageHub.java:412)
    at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:64)
    at org.gradle.internal.concurrent.ManagedExecutorImpl$1.run(ManagedExecutorImpl.java:48)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at org.gradle.internal.concurrent.ThreadFactoryImpl$ManagedThreadRunnable.run(ThreadFactoryImpl.java:56)
    at java.lang.Thread.run(Thread.java:748) 

using logic for validating like:

public void parse(boolean validate) throws ParserConfigurationException, SAXException, IOException {
            
    System.out.println("Invoking parse()");
    // obtain DOM parser
    DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
    
    try{
        dbf.setFeature("http://xml.org/sax/features/

Answer 1

The error,

cvc-elt.1: Cannot find the declaration of element xsd:schema without namespaces?

commonly indicates a mistaken attempt to pass an XSD to a validator as the subject of the validation rather than passing the intended XML file.

In your case, make sure that xmlFileName is for an XML file, not an XSD.

On the other hand, if you actually want to validate the XSD itself, see

• Validating XSD itself
• XML Schema to validate XML Schemas?