HashSet<Integer> toRemove = new HashSet<Integer>(); 
for (Map.Entry<Character, MutableInt> e : occurrences.entrySet()) { 
  Character v = e.getKey(); 
  int found = 0; 
  for (int i = 0, ct = e.getValue().intValue(); i < ct; i++) { 
    found = indexOf(array, v.charValue(), found); 
    if (found < 0) { 
      break; 
    } 
    toRemove.add(found++); 
  } 
} 
 
 
return (char[]) removeAll((Object)array, extractIndices(toRemove)); 

BitSet toRemove = new BitSet(); 
for (Map.Entry<Character, MutableInt> e : occurrences.entrySet()) { 
  Character v = e.getKey(); 
  int found = 0; 
  for (int i = 0, ct = e.getValue().intValue(); i < ct; i++) { 
    found = indexOf(array, v.charValue(), found); 
    if (found < 0) { 
      break; 
    } 
    toRemove.set(found++); 
  } 
} 
return (char[]) removeAll(array, toRemove);