static public long nextAddr(Random r,WormAddressManager am){
  if (r.nextInt(100) < 5)   return 0L;
  return nextNonZeroAddr(r,am);
}

static public long nextAddr ( Random r , WormAddressManager am ) { if ( r . nextInt ( 100 ) < 5 ) return 0L ; return nextNonZeroAddr ( r , am ) ; }
returns a legal random address and null 5 % of the time .
