出现好多红色提醒，这些事什么意思

我按照老师说的去打，为什么会出现下面这么多错误

com.sun.org.apache.xerces.internal.impl.io.MalformedByteSequenceException: 1 字节的 UTF-8 序列的字节 1 无效。

at com.sun.org.apache.xerces.internal.impl.io.UTF8Reader.invalidByte(UTF8Reader.java:701)

at com.sun.org.apache.xerces.internal.impl.io.UTF8Reader.read(UTF8Reader.java:567)

at com.sun.org.apache.xerces.internal.impl.XMLEntityScanner.load(XMLEntityScanner.java:1896)

at com.sun.org.apache.xerces.internal.impl.XMLEntityScanner.scanContent(XMLEntityScanner.java:1032)

at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:2814)

at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:606)

at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:504)

at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:848)

at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:777)

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.imooc.dmtest.test.DOMTest.main(DOMTest.java:23)