findAllEmaiLFields.CreateDummyEmails.cls

public static Map < String, List < String >> findAllEmaiLFields() {
  Map < String, List < String >> mSObjEmailFields = new Map < String, List < String >> ();
  // Iterate through all SObjects
  for (SObjectType sObjType: Schema.getGlobalDescribe().values()) {
   DescribeSObjectResult sObjDescribe = sObjType.getDescribe();
   // Avoid objects that cannot be queried or updated.
   if (!sObjDescribe.isQueryable() || !sObjDescribe.isUpdateable()) continue;
   String sObjName = sObjDescribe.getName();
   // Iterate through all fields 
   for (SObjectField sObjField: sObjDescribe.fields.getMap().values()) {
    DescribeFieldResult sObjFld = sObjField.getDescribe();
    // Consider only Email fields
    if (sObjFld.getType() != Schema.DisplayType.EMAIL) continue;
    if (!sObjFld.isFilterable()) continue;
    // Add all Email fields in the map.
    if (mSObjEmailFields.containsKey(sObjName)) {
     mSObjEmailFields.get(sObjName).add(sObjFld.getName());
    } else {
     mSObjEmailFields.put(sObjName, new List < String > {
      sObjFld.getName()
     });
    }
   }
  }
  return mSObjEmailFields;
 }