Metadata Query Apex Class

Sample SOAP Message Request - Querying an Apex Class

<?xml version="1.0" encoding="UTF-8"?>
<env:Envelope xmlns:env="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <env:Header>
    <SessionHeader xmlns="urn:enterprise.soap.sforce.com">
      <sessionId>3e8700Dx00000007Rot!lHt1wncqJisdfgvbrtadc7TudeWkY7SdwrRf2wCR39e_RsWvG7B.OSZIX6U6sqUqYIuBKhpwn3JLMpBWVCx1ajmbuoeyvxL07YvPnHAgqfhk8W21T0HYaZMiswCW</sessionId>
    </SessionHeader>
    <CallOptions xmlns="urn:enterprise.soap.sforce.com">
      <defaultNamespace xsi:nil="true" />
      <clientLog xsi:nil="true" />
      <debugExceptions>true</debugExceptions>
      <platform xsi:nil="true" /><remoteApplication xsi:nil="true" />
    </CallOptions>
  </env:Header>
  <env:Body>
    <m:query xmlns:m="urn:enterprise.soap.sforce.com" xmlns:sobj="urn:sobject.enterprise.soap.sforce.com">
      <m:queryString>select id from apexclass</m:queryString>
    </m:query>
  </env:Body>
</env:Envelope>

Sample SOAP Response

<?xml version="1.0" encoding="UTF-8"?>
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns="urn:enterprise.soap.sforce.com" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:sf="urn:sobject.enterprise.soap.sforce.com">
  <soapenv:Body>
    <queryResponse>
      <result>
        <done>true</done>
        <queryLocator xsi:nil="true"/>
        <records xsi:type="sf:CustomEntityDefinition">
          <sf:Id>01Ix0000000DRnfEAG</sf:Id>
        </records>
        <size>1</size>
      </result>
    </queryResponse>
  </soapenv:Body>
</soapenv:Envelope>