String feature = "";
<BUG>if (_j != _i) {
</BUG>
int a = (int)(ab >> 32);
<BUG>final String fA = a != _missing ? _fr.domains()[_i][a] : "NA";
</BUG>
feature = fA + "_";
}
int b = (int) ab;
<BUG>String fB = b != _missing ? _fr.domains()[_j][b] : "NA";
</BUG>
feature += fB;

String feature = "";
if (dA != dB) {
int a = (int)(ab >> 32);
final String fA = a != _missing ? dA[a] : "NA";
feature = fA + "_";
}
int b = (int) ab;
String fB = b != _missing ? dB[b] : "NA";
feature += fB;
