### Question:
MUXPool extends QBeanSupport implements MUX, MUXPoolMBean { public ISOMsg request (ISOMsg m, long timeout) throws ISOException { long maxWait = System.currentTimeMillis() + timeout; MUX mux = getMUX(m,maxWait); if (mux != null) { timeout = maxWait - System.currentTimeMillis(); if (timeout >= 0) return mux.request (m, timeout); } return null; }  void initService(); void stopService(); ISOMsg request(ISOMsg m, long timeout); void send(ISOMsg m); boolean isConnected(); void request(ISOMsg m, long timeout, final ISOResponseListener r, final Object handBack); @Override String[] getMuxNames(); @Override int getStrategy(); static final int ROUND_ROBIN; static final int PRIMARY_SECONDARY; static final int ROUND_ROBIN_WITH_OVERRIDE; static final int SPLIT_BY_DIVISOR; }### Answer:
@Test public void testRequestThrowsNullPointerException() throws Throwable { MUXPool mUXPool = new MUXPool(); try { mUXPool.request(new ISOMsg("testMUXPoolMti"), 100L); fail("Expected NullPointerException to be thrown"); } catch (NullPointerException ex) { if (isJavaVersionAtMost(JAVA_14)) { assertNull(ex.getMessage(), "ex.getMessage()"); } else { assertEquals("Cannot read the array length because \"<local4>\" is null", ex.getMessage(), "ex.getMessage()"); } } }