Mersenne twister (Java)

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This program implements the Mersenne twister algorithm for generation of pseudorandom numbers. The original code was written by Michael Brundage and has been placed in the public domain. [1] 

<<MT.java>>=
public final class MT {
    private int mt_index;
    private int[] mt_buffer = new int[624];
    public MT() {
        java.util.Random r = new java.util.Random();
        for (int i = 0; i < 624; i++)
            mt_buffer[i] = r.nextInt();
        mt_index = 0;
    }
    public int random() {
        if (mt_index == 624)
        {
            mt_index = 0;
            int i = 0;
            int s;
            for (; i < 624 - 397; i++) {
                s = (mt_buffer[i] & 0x80000000) | (mt_buffer[i+1] & 0x7FFFFFFF);
                mt_buffer[i] = mt_buffer[i + 397] ^ (s >> 1) ^ ((s & 1) * 0x9908B0DF);
            }
            for (; i < 623; i++) {
                s = (mt_buffer[i] & 0x80000000) | (mt_buffer[i+1] & 0x7FFFFFFF);
                mt_buffer[i] = mt_buffer[i - (624 - 397)] ^ (s >> 1) ^ ((s & 1) * 0x9908B0DF);
            }
            s = (mt_buffer[623] & 0x80000000) | (mt_buffer[0] & 0x7FFFFFFF);
            mt_buffer[623] = mt_buffer[396] ^ (s >> 1) ^ ((s & 1) * 0x9908B0DF);
        }
        return mt_buffer[mt_index++];
    }
}
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