### Question:
ExceptionLogFilter implements LogListener { public synchronized LogEvent log (LogEvent evt) { synchronized (evt.getPayLoad()) { for (Object o : evt.getPayLoad()) { if (o instanceof Throwable) return evt; } } return null; } ExceptionLogFilter(); synchronized LogEvent log(LogEvent evt);  }### Answer:
@Test public void testLog() throws Throwable { LogEvent result = new ExceptionLogFilter().log(new LogEvent()); assertNull(result, "result"); }