BarcodeGeneratorProvider { public Collection<String> getAvailableBarcodeGenerators() { final Set<String> res = new TreeSet<String>(); res.addAll(barcodeGenerators.keySet()); return res; } private  BarcodeGeneratorProvider(); static synchronized BarcodeGeneratorProvider getInstance(); Collection<String> getAvailableBarcodeGenerators(); BarcodeGenerator getBarcodeGenerator(String id);  }
@Test public void getAvailableBarcodeGenerators() { System.out.println("getAvailableBarcodeGenerators"); BarcodeGeneratorProvider instance = BarcodeGeneratorProvider.getInstance(); Collection<String> result = instance.getAvailableBarcodeGenerators(); assertNotNull(result); assertTrue("some generators loadable", result.size() > 0); }