private boolean vowelInStem() {
    for (int i = 0; i < stemLength(); i++) {
      if (isVowel(i)) return true;
    }
    return false;
  }
*
YCS: this was the one place where lookup was not followed by return.
So restructure it. if ((j>0)&&(lookup(word.toString())) &&
!((word.charAt(j) == 's') && (word.charAt(j-1) == 's'))) return;
***
linguistics/src/main/java/com/yahoo/language/simple/kstem/KStemmer.java