SequenceIntervalCollection whenActive = bugInstance.getActiveIntervalCollection();
	public MineBugHistory execute() {		int maxSequence = (int)bugCollection.getSequenceNumber();		versionList = new Version[maxSequence + 1];		for (int i = 0; i <= maxSequence; ++i) {			versionList[i] = new Version(i);		}				for (Iterator<AppVersion> i = bugCollection.appVersionIterator(); i.hasNext();) {			AppVersion appVersion = i.next();			sequenceToAppVersionMap.put(Long.valueOf(appVersion.getSequenceNumber()), appVersion);		}		sequenceToAppVersionMap.put(			Long.valueOf(bugCollection.getSequenceNumber()),			bugCollection.getCurrentAppVersion());				for (Iterator<BugInstance> j = bugCollection.iterator(); j.hasNext();) {			BugInstance bugInstance = j.next();			if (ignore(bugInstance))				continue;			for (int i = 1; i <= maxSequence; ++i) {				SequenceIntervalCollection whenActive = bugInstance.getActiveIntervalCollection();								boolean activePrevious = whenActive.contains(((long)i) -1);				boolean activeCurrent = whenActive.contains((long)i);								int key = getKey(activePrevious, activeCurrent);				versionList[i].increment(key);			}		}				return this;	}