import org.adempiere.webui.adwindow.ADWindowContent.ADWindowVlayout;
import org.adempiere.webui.adwindow.AbstractADWindowContent;
import org.adempiere.webui.session.SessionManager;
import org.compiere.util.Env;
import org.compiere.util.DB;
import org.compiere.util.Util;
import java.math.*;
import java.sql.Timestamp;
import java.util.Calendar;
import java.util.Date;
if((A_Tab.getValue("M_Product_ID") != null)  ) {
   ADWindowVlayout pop = ((ADWindowVlayout)SessionManager.getAppDesktop().getActiveWindow());
   f = pop.getClass().getDeclaredField("content");
   f.setAccessible(true);
   AbstractADWindowContent content = (AbstractADWindowContent)f.get(pop);
  A_Tab.setValue("LIT_Barcode", ""); 
   content.onSaveCreate();
} 
Marco