private short addEntry(Entry entry){
  pool.add(entry);
  if (pool.size() >= 65535) {
    throw new IllegalArgumentException("constant pool size limit exceeded");
  }
  return (short)pool.size();
}

private short addEntry ( Entry entry ) { pool . add ( entry ) ; if ( pool . size ( ) >= 65535 ) { throw new IllegalArgumentException ( "constant pool size limit exceeded" ) ; } return ( short ) pool . size ( ) ; }
add a new constant pool entry and return its index .
