if (classNameToObligationMap.put(className, new Obligation(className, nextId)) != null) {
Obligation obligation = new Obligation(className, nextId); if (classNameToObligationMap.put(className, obligation) != null) {
	public void addObligation(String className) {		int nextId = classNameToObligationMap.size();		if (classNameToObligationMap.put(className, new Obligation(className, nextId)) != null) {			throw new IllegalStateException("Obligation " + className +				" added multiple times");		}	}