@Override
    public String toString() {
      return new StringBuilder().append(keys[pos]).append('=')
        .append((values[pos] == CharArrayMap.this) ? "(this Map)" : values[pos])
        .toString();
    }
use nextCharArray() + currentValue() for better efficiency.
linguistics/src/main/java/com/yahoo/language/simple/kstem/CharArrayMap.java