question: private void bindEntityId ( Class < ? > cls , String type , AccessibleObject fieldOrMethod ) { String fieldName = getFieldName ( fieldOrMethod ) ; Class < ? > fieldType = getFieldType ( fieldOrMethod ) ; fieldsToTypes . put ( fieldName , fieldType ) ; idField = fieldOrMethod ; idType = fieldType ; idFieldName = fieldName ; fieldsToValues . put ( fieldName , fieldOrMethod ) ; if ( idField != null && ! fieldOrMethod . equals ( idField ) ) { throw new DuplicateMappingException ( type + " " + cls . getName ( ) + ":" + fieldName ) ; } }
target:  Bind an id field to an entity.