Java - HashMap efficiency

[sefie20]

I am implementing a compression algortihm using a HashMap and TreeMap. When I compress a file consisting only of the ASCII character 255, they are both about the same in the time they take to compress. However, when I have a file that has only the 0 character from ASCII (which is just a blank space) the HashMap takes considerably longer, but the TreeMap is about the same. (Note the two files are the exact same size). Thanks a lot

 

[you2]

Might be the cost of the hash function with no advantage. With the treemap it is comparing the element against other elements in the tree -but no overhead for hash function.