Java Fastest Hash Function

Question

I have a Boolean string (like "01100..001") of length 128 characters (means 128 number of 0/1). I am searching for an efficient (fast) hash function in Java, which produce a much lower representation than 128 bit and obviously with less collision. Can anybody help me, is there any such hash function ? Any suggestion ?

Answer 1

Try using the .hashCode() method on Java String class, it returns an int and it is very fast.

Or you can use the .hashCode() method on java.util.BitSet as Pulsar suggest, if you prefer store your data in BitSet.

Answer 2

Have you considered using a java.util.BitSet instead, depending on what you are doing it could be a lot easier and more efficient? http://docs.oracle.com/javase/6/docs/api/java/util/BitSet.html It has a .hashCode() method as well.

Answer 3

If you need to calculate the hash of a string, simply use the hashCode() method of the String class. Depending on the implementation, several optimizations are made for quickly computing this value.

As an example, in OpenJDK's implementation of the String class the hashCode() method caches the value in the hash attribute and only needs to be computed once.

And who said that a string of 128 characters has a hash of 128-bits? all hashes returned by the hashCode() method in Java are of type int, and ints in Java are represented using 32-bits.