Best hashing algorithm in terms of hash collisions and performance for strings

Question

What would be the best hashing algorithm if we had the following priorities (in that order):

1. Minimal hash collisions
2. Performance

It doe

Answer 1

The simple hashCode used by Java's String class might show a suitable algorithm.

Below is the "GNU Classpath" implementation. (License: GPL)

  /**
   * Computes the hashcode for this String. This is done with int arithmetic,
   * where ** represents exponentiation, by this formula:

   * s[0]*31**(n-1) + s[1]*31**(n-2) + ... + s[n-1].
   *
   * @return hashcode value of this String
   */
  public int hashCode()
  {
    if (cachedHashCode != 0)
      return cachedHashCode;

    // Compute the hash code using a local variable to be reentrant.
    int hashCode = 0;
    int limit = count + offset;
    for (int i = offset; i < limit; i++)
      hashCode = hashCode * 31 + value[i];
    return cachedHashCode = hashCode;
  }