The field ZipEntry.flags has no meaningful use outside ZipInputStream and could be moved to an internal field in ZipInputStream.XEntry. This saves four bytes from the ZipEntry object size and also a read in ZipFile.getZipEntry.

History:

In 2009, JDK-5030283 moved the "flags" field from ZipOutputStream.XEntry to ZipEntry. The change implemented support for non-UTF-8 charsets when reading ZIP entry names and comments. It's unclear why the field move was deemed neccessary.