in flume-kafka-source/src/main/java/org/apache/flume/source/kafka/KafkaSource.java [462:468]
private static Map<String, String> toStringMap(Map<CharSequence, CharSequence> charSeqMap) {
Map<String, String> stringMap = new HashMap<String, String>();
for (Map.Entry<CharSequence, CharSequence> entry : charSeqMap.entrySet()) {
stringMap.put(entry.getKey().toString(), entry.getValue().toString());
}
return stringMap;
}