### Question:
FilterLogListener implements LogListener,Configurable { public synchronized void close() { if (p != null) { p.close(); p = null; } } FilterLogListener();  FilterLogListener(PrintStream p); @Override void setConfiguration(Configuration cfg); synchronized void setPrintStream(PrintStream p); synchronized void close(); String getPriority(); void setPriority(String priority); boolean permitLogging(String tagLevel); @Override synchronized LogEvent log(LogEvent ev);  }### Answer:
@Test public void testClose() throws Throwable { FilterLogListener filterLogListener = new FilterLogListener(); filterLogListener.close(); filterLogListener.close(); assertNull(filterLogListener.p, "filterLogListener.p"); }
@Test public void testClose1() throws Throwable { FilterLogListener filterLogListener = new FilterLogListener(); filterLogListener.close(); assertNull(filterLogListener.p, "filterLogListener.p"); }