### Question:
PropertyUtils { public static Boolean getBoolean(String key) { if (StringUtils.isEmpty(key)) { return false; } String value = properties.getProperty(key.trim()); if(null != value){ return Boolean.parseBoolean(value); } return false; } private  PropertyUtils(); static String getString(String key); static String getString(String key, String defaultVal); static int getInt(String key); static int getInt(String key, int defaultValue); static Boolean getBoolean(String key); static long getLong(String key); static long getLong(String key, long defaultVal); static double getDouble(String key); static double getDouble(String key, double defaultVal); static String[] getArray(String key, String splitStr); static T getEnum(String key, Class<T> type,
                                         T defaultValue);  }### Answer:
@Test public void testGetBoolean() { Boolean result = PropertyUtils.getBoolean("mail.smtp.starttls.enable"); assertTrue(result); result = PropertyUtils.getBoolean("mail.smtp.ssl.enable"); assertFalse(result); result = PropertyUtils.getBoolean("abc"); assertFalse(result); result = PropertyUtils.getBoolean(null); assertFalse(result); }