関連ワード:  how to stream map in java 8    how to stream hashmap in java 8    how to use stream map in java 8    how to collect stream to map in java 8    how to convert stream to map in java 8    how to print map in java 8 stream    how to use stream map and filter in java 8    stream map in java 8 example    how to iterate map in java 8 using stream    how to iterate hashmap in java 8 stream