Difference between getFreespace() and getUsableSpace of File

Question

I could not point out exact difference between getFreeSpace() and getUsableSpace() method of File class. When i run following code

Answer 1

The java.io.File.getFreeSpace() method returns the number of unallocated bytes in the partition named by this abstract path name. The returned number of unallocated bytes are not a gurantee. The count of unallocated bytes is likely to be accurate immediately after this call and inaccurate by any external I/O operations.

The java.io.File.getUsableSpace() method returns the number of bytes available to this virtual machine on the partitioned named by this abstract name. This method usually provide a more accurate estimate of how much new data can actually be written as this method checks for write permissions and other operating system restrictions.