https://docs.oracle.com/javase/jp/8/docs/api/java/nio/file/spi/FileTypeDetector.html
FileTypeDetector (Java Platform SE 8)
java platformse
https://developer.android.com/reference/java/nio/file/spi/FileTypeDetector?authuser=19
FileTypeDetector | API reference | Android Developers
api referenceandroiddevelopers