if(credits.longValue() <= length) {
if(credits != null && credits.longValue() <= length) {
    private void determineCreditors(Address dest, int length) {        boolean multicast=dest == null || dest.isMulticastAddress();        Address mbr;        Long    credits;        if(multicast) {            Map.Entry entry;            for(Iterator it=sent.entrySet().iterator(); it.hasNext();) {                entry=(Map.Entry)it.next();                mbr=(Address)entry.getKey();                credits=(Long)entry.getValue();                if(credits.longValue() <= length) {                    if(!creditors.contains(mbr))                        creditors.add(mbr);                }            }        }        else {            credits=(Long)sent.get(dest);            if(credits.longValue() <= length) {                if(!creditors.contains(dest))                    creditors.add(dest);            }        }    }