final String r = a.replaceAll(" .*?(?=_)", "");
si imprime la r, dio salida:
000003023_AggregateStopLossLimit_W_2012-12-22.PDF
final String r = a.replaceAll(" .*?(?=_)", "");
si imprime la r, dio salida:
000003023_AggregateStopLossLimit_W_2012-12-22.PDF