### Question:
SimpleKeyFile implements SecureKeyStore, Configurable, LogSource { @Override public synchronized void setKey (String alias, SecureKey secureKey) throws SecureKeyStoreException { LogEvent evt = new LogEvent(this, "set-key"); evt.addMessage("alias", alias); evt.addMessage(secureKey); try { if (!(secureKey instanceof SecureDESKey)) throw new SecureKeyStoreException("Unsupported SecureKey class: " + secureKey.getClass().getName()); load(); setProperty(alias, "class", secureKey.getClass().getName()); setProperty(alias, "key", ISOUtil.hexString(secureKey.getKeyBytes())); setProperty(alias, "length", Short.toString(secureKey.getKeyLength())); setProperty(alias, "type", secureKey.getKeyType()); String keyCheckValueHexString = ISOUtil.hexString(((SecureDESKey)secureKey).getKeyCheckValue()); setProperty(alias, "checkvalue", keyCheckValueHexString); store(); } catch (Exception e) { evt.addMessage(e); throw e instanceof SecureKeyStoreException ? (SecureKeyStoreException) e : new SecureKeyStoreException(e); } finally { Logger.log(evt); } } SimpleKeyFile();  SimpleKeyFile(String keyFileName); void init(String keyFileName); @Override void setLogger(Logger logger, String realm); @Override Logger getLogger(); @Override String getRealm(); @Override void setConfiguration(Configuration cfg); @Override synchronized SecureKey getKey(String alias); @Override synchronized void setKey(String alias, SecureKey secureKey); String getProperty(String alias, String subName); void setProperty(String alias, String subName, String value); @Override Map<String, SecureKey> getKeys();  }### Answer:
@Test public void testSetKeyThrowsSecureKeyStoreException() throws Throwable { SimpleKeyFile simpleKeyFile = new SimpleKeyFile(); try { simpleKeyFile.setKey("testSimpleKeyFileAlias", null); fail("Expected SecureKeyStoreException to be thrown"); } catch (SecureKeyStore.SecureKeyStoreException ex) { if (isJavaVersionAtMost(JAVA_14)) { assertEquals("java.lang.NullPointerException", ex.getMessage(), "ex.getMessage()"); assertNull(ex.getNested().getMessage(), "ex.getNested().getMessage()"); } else { assertEquals("java.lang.NullPointerException: Cannot invoke \"Object.getClass()\" because \"secureKey\" is null", ex.getMessage(), "ex.getMessage()"); assertEquals("Cannot invoke \"Object.getClass()\" because \"secureKey\" is null", ex.getNested().getMessage(), "ex.getNested().getMessage()"); } assertEquals(0, simpleKeyFile.props.size(), "simpleKeyFile.props.size()"); assertNull(simpleKeyFile.file, "simpleKeyFile.file"); } }