What is the difference between `##` and `hashCode`?

Question

What is the difference between methods ## and hashCode?

They seem to be outputting the same values no matter which class or hashCode

Answer 1

Just want to add to the answers of other posters that although the ## method strives to keep the contract between equality and hash codes, it is apparently not good enough in some cases, like when you are comparing doubles and longs (scala 2.10.2):

> import java.lang._
import java.lang._

> val lng = Integer.MAX_VALUE.toLong + 1
lng: Long = 2147483648

> val dbl = Integer.MAX_VALUE.toDouble + 1
dbl: Double = 2.147483648E9

> lng == dbl
res65: Boolean = true

> lng.## == dbl.##
res66: Boolean = false

> (lng.##, lng.hashCode)
res67: (Int, Int) = (-2147483647,-2147483648)

> (dbl.##, dbl.hashCode)
res68: (Int, Int) = (-2147483648,1105199104)