package com.test;

import com.fasterxml.jackson.dataformat.xml.XmlMapper;
import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlProperty;
import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlRootElement;

import java.io.Serializable;

public class Test {
    public static void main(String[] args) throws Exception {
        char[] chars = new char[2];
        chars[0] = 0xffff;
        chars[1] = 'A';
        String info = new String(chars);
        System.out.println(info);
        Other other = new Other();
        other.setInfo(info);
        XmlMapper xmlMapper = new XmlMapper();
        String otherXml = xmlMapper.writeValueAsString(other);
        System.out.println(otherXml);
        Other other1 = xmlMapper.readValue(otherXml, Other.class);
        System.out.println(other1.getInfo());
    }

    @JacksonXmlRootElement(localName = "Other")
    public static class Other implements Serializable {
        @JacksonXmlProperty(localName = "Info")
        private String info;
        
	public String getInfo() {
            return info;
        }

        public void setInfo(String info) {
            this.info = info;
        }
    }
}

running result:

�A
<Other><Info>&#xffff;A</Info></Other>
Exception in thread "main" com.fasterxml.jackson.core.JsonParseException: Illegal character entity: expansion character (code 0xffff)
 at [row,col {unknown-source}]: [1,21]
 at [Source: (StringReader); line: 1, column: 22]
	at com.fasterxml.jackson.dataformat.xml.util.StaxUtil.throwAsParseException(StaxUtil.java:25)
	at com.fasterxml.jackson.dataformat.xml.deser.FromXmlParser._nextToken(FromXmlParser.java:1460)
	at com.fasterxml.jackson.dataformat.xml.deser.FromXmlParser.nextToken(FromXmlParser.java:746)
	at com.fasterxml.jackson.databind.deser.BeanDeserializer.vanillaDeserialize(BeanDeserializer.java:305)
	at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:177)
	at com.fasterxml.jackson.dataformat.xml.deser.XmlDeserializationContext.readRootValue(XmlDeserializationContext.java:104)
	at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:4931)
	at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3868)
	at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3836)
	at com.test.Test.main(Test.java:21)
Caused by: com.ctc.wstx.exc.WstxParsingException: Illegal character entity: expansion character (code 0xffff)
 at [row,col {unknown-source}]: [1,21]
	at com.ctc.wstx.sr.StreamScanner.constructWfcException(StreamScanner.java:634)
	at com.ctc.wstx.sr.StreamScanner.throwParseError(StreamScanner.java:504)
	at com.ctc.wstx.sr.StreamScanner.reportIllegalChar(StreamScanner.java:2463)
	at com.ctc.wstx.sr.StreamScanner.validateChar(StreamScanner.java:2400)
	at com.ctc.wstx.sr.StreamScanner.resolveCharEnt(StreamScanner.java:2376)
	at com.ctc.wstx.sr.StreamScanner.fullyResolveEntity(StreamScanner.java:1524)
	at com.ctc.wstx.sr.BasicStreamReader.nextFromTree(BasicStreamReader.java:2838)
	at com.ctc.wstx.sr.BasicStreamReader.next(BasicStreamReader.java:1122)
	at com.fasterxml.jackson.dataformat.xml.deser.XmlTokenStream._collectUntilTag(XmlTokenStream.java:568)
	at com.fasterxml.jackson.dataformat.xml.deser.XmlTokenStream._next(XmlTokenStream.java:473)
	at com.fasterxml.jackson.dataformat.xml.deser.XmlTokenStream.next(XmlTokenStream.java:313)
	at com.fasterxml.jackson.dataformat.xml.deser.FromXmlParser._nextToken(FromXmlParser.java:1458)
	... 8 more