RFR JDK-6233323: ZipEntry.isDirectory() may return false incorrectly

[Xueming Shen]

Hi,

Please help codereview the change for  JDK-6233323/8144977

issue:
https://bugs.openjdk.java.net/browse/JDK-6233323
https://bugs.openjdk.java.net/browse/JDK-8144977

webrev: http://cr.openjdk.java.net/~sherman/62333233_8144977/webrev

This is an implementation issue from day-one. ZIP spec specifies the
name of a directory entry must be ended with a slash, so a directory
name "dir" in ZIP world should have the name "dir/".

ZipFile.getEntry() works well with these type of "canonicalized" directory
names. However, its implementation also tries to be "liberal" when
taking name that doesn't end with "/". Where there is no such entry (file)
found, it tries a second lookup with a "/" appended, and returns such entry
if find one. The original implementation always to use the original passed
in name (the one without the ending slash) as the entry name for the
returned ZipEntry. This is fine if the entry is from the first round of lookup,
in which the name stored in zip file matches the passed in name and to
use the name directly obviously helps avoiding creating another String
object from the binary name (byte[] in zip entry). But in case of the entry
is from the second round lookup, the direct consequence is the isDirectory()
method of the returned entry always returns false (ZipEntry.isDirectory()
implementation simply checks if the name ends with / or not), even it is
actually a directory entry.

The fix is to simply return the name stored in the zip file. It appears this
should be the desired and expected result.

Thanks,
Sherman