@Override
    public int hashCode() {
        int hash = 37;
        hash += 37 * hash + Float.floatToIntBits(x);
        hash += 37 * hash + Float.floatToIntBits(y);
        hash += 37 * hash + Float.floatToIntBits(z);
        hash += 37 * hash + Float.floatToIntBits(w);
        return hash;
    }
<code>hashCode</code> returns a unique code for this vector object based
on its values. If two vectors are logically equivalent, they will return
the same hash code value.

@return the hash code value of this vector.
jme3-core/src/main/java/com/jme3/math/Vector4f.java