If email body contains U+FFFF, the API returns 500 Internal Server Error:

EwsRequest:

<Trace Tag="EwsRequest" Tid="8777" Time="2016-02-05 00:17:58Z">
    <?xml version="1.0" encoding="utf-8"?>
    <soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                   xmlns:m="http://schemas.microsoft.com/exchange/services/2006/messages" xmlns:t="http://schemas.microsoft.com/exchange/services/2006/types">
        <soap:Header>
            <t:RequestServerVersion Version="Exchange2010_SP2"></t:RequestServerVersion>
        </soap:Header>
        <soap:Body>
            <m:CreateItem MessageDisposition="SendAndSaveCopy">
                <m:SavedItemFolderId>
                    <t:DistinguishedFolderId Id="sentitems"></t:DistinguishedFolderId>
                </m:SavedItemFolderId>
                <m:Items>
                    <t:Message>
                        <t:Subject>Test</t:Subject>
                        <t:Body BodyType="HTML">Hello World</t:Body>
                        <t:ToRecipients>
                            <t:Mailbox>
                                <t:EmailAddress>pbhowmick@coatue.com</t:EmailAddress>
                            </t:Mailbox>
                        </t:ToRecipients>
                    </t:Message>
                </m:Items>
            </m:CreateItem>
        </soap:Body>
    </soap:Envelope>
</Trace>

EwsResponse :

<Trace Tag="EwsResponse" Tid="8777" Time="2016-02-05 00:17:58Z">
    <?xml version="1.0" encoding="utf-8"?>
    <s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/">
        <s:Body>
            <s:Fault>
                <faultcode xmlns:a="http://schemas.microsoft.com/exchange/services/2006/types">a:ErrorSchemaValidation</faultcode>
                <faultstring xml:lang="en-US">The request failed schema validation: '&#xFFFF;', hexadecimal value 0xFFFF, is an invalid character. Line 1,
                    position 653.
                </faultstring>
                <detail>
                    <e:ResponseCode xmlns:e="http://schemas.microsoft.com/exchange/services/2006/errors">ErrorSchemaValidation</e:ResponseCode>
                    <e:Message xmlns:e="http://schemas.microsoft.com/exchange/services/2006/errors">The request failed schema validation.</e:Message>
                    <t:MessageXml xmlns:t="http://schemas.microsoft.com/exchange/services/2006/types">
                        <t:LineNumber>1</t:LineNumber>
                        <t:LinePosition>653</t:LinePosition>
                        <t:Violation>'&#xFFFF;', hexadecimal value 0xFFFF, is an invalid character. Line 1, position 653.</t:Violation>
                    </t:MessageXml>
                </detail>
            </s:Fault>
        </s:Body>
    </s:Envelope>
</Trace>

This is what the Java API returns:

2016-02-05 00:17:58.669 UTC [error] application play-akka.actor.default-dispatcher-10 requestId=4
microsoft.exchange.webservices.data.core.exception.service.remote.ServiceRequestException: The request failed. The request failed. The remote server returned an error: (500)Internal Server Error
 at microsoft.exchange.webservices.data.core.request.SimpleServiceRequestBase.internalExecute(SimpleServiceRequestBase.java:74) ~[ews-java-api-2.0.jar:na]
 at microsoft.exchange.webservices.data.core.request.MultiResponseServiceRequest.execute(MultiResponseServiceRequest.java:158) ~[ews-java-api-2.0.jar:na]
 at microsoft.exchange.webservices.data.core.ExchangeService.internalCreateItems(ExchangeService.java:598) ~[ews-java-api-2.0.jar:na]
 at microsoft.exchange.webservices.data.core.ExchangeService.createItem(ExchangeService.java:657) ~[ews-java-api-2.0.jar:na]
 at microsoft.exchange.webservices.data.core.service.item.Item.internalCreate(Item.java:245) ~[ews-java-api-2.0.jar:na]
 at microsoft.exchange.webservices.data.core.service.item.EmailMessage.internalSend(EmailMessage.java:147) ~[ews-java-api-2.0.jar:na]
 at microsoft.exchange.webservices.data.core.service.item.EmailMessage.sendAndSaveCopy(EmailMessage.java:300) ~[ews-java-api-2.0.jar:na]

Sanitization is handled by the .NET library and should also be handled by the Java library.

See MSDN docs: https://technet.microsoft.com/en-us/library/gg585107(v=exchg.80).aspx

OfficeDev / ews-java-api

If email body contains U+FFFF, the API returns 500 Internal Server Error: #490