Recursive Bubble Sort!

class Bt {
    int[] unsorted={3,5,2,0,1,8,6,-1};
    int[] candidate;
    int[] best;
    public static void main (String[] args) {
        Bt b= new Bt();
        b.bt();
        b.print(b.best);
    }
    void bt() {
        if (accept (candidate)) {
            best= new int[candidate.length];
            System.arraycopy (candidate, 0, best, 0, candidate.length);
            return;
            //System.exit (0);
        }
        if (reject (candidate)) return;
        if (!augment ()) return;
        do {
            bt();
        } while (next());
        diminish ();
    }
    public boolean augment () {
        if (candidate==null) {
            candidate= new int[1];
            candidate[0]=0;
            return true;
        }
        int i;
        boolean b[]= new boolean [unsorted.length];
        // add the smallest index not present
        for (i=0;i<candidate.length;i++)
            b[candidate[i]]=true;
//      for (i=candidate[candidate.length-1];i<unsorted.length;i++)
        for (i=0;i<unsorted.length;i++)
            if (!b[i]) break;
        // add one element if possible.
        if(i<unsorted.length) {
            int r[]= new int[candidate.length+1];
            System.arraycopy (candidate, 0, r, 0, candidate.length);
            r[r.length-1]=i;
            candidate=r;
            return true;
        }
        return false;
    }
    public boolean next () {
        if (candidate==null) {
            System.out.println ("cannot be empty.");
            System.exit (0);
        }
        int i;
        boolean b[]= new boolean [unsorted.length];
        // add the smallest index not present
        for (i=0;i<candidate.length;i++)
            b[candidate[i]]=true;
        for (i=candidate[candidate.length-1];i<unsorted.length;i++)
            if (!b[i]) break;
        // substitute the last element if possible.
        if(i<unsorted.length) {
            candidate[candidate.length-1]=i;
            return true;
        }
        return false;
    }
    public void diminish () {
        if ((candidate!=null)&&(candidate.length>0)) {
            int r[]= new int[candidate.length-1];
            System.arraycopy (candidate, 0, r, 0, candidate.length-1);
            candidate=r;
        }
    }
    public boolean accept (int[] candidate) {
        if (candidate==null) return false;
        if (!reject(candidate) && candidate.length==unsorted.length) return true;
        return false;
    }
    public boolean reject (int[] candidate) {
        if ((candidate==null)||(candidate.length<2)) return false;
        int i;
        for (i=1;i<candidate.length;i++)
            if (unsorted[candidate[i-1]]>unsorted[candidate[i]]) return true;
        return false;
    }
    public void print (int[] a) {
        if (a==null) {
            System.out.println ("Empty");
            return;
        }
        for (int i=0;i<a.length;i++)
            System.out.print (a[i] + " ");
        System.out.println();
    }
}