A DESCRIPTION OF THE PROBLEM :
https://github.com/openjdk/jdk/blob/9e570105c30a6e462d08931e2010cef9cd5a6031/src/java.base/windows/classes/sun/nio/ch/FileKey.java stores nFileIndexHigh and nFileIndexLow as longs. However, the Windows API declares these fields as 32-bit DWORDs. Therefore, this class is wasting half the storage for those fields, and should store them as int.