### Question:
Sys { public static String sysProp(String key) { return _sysProp(key, null); }  static void println( String message ); static void print( String message ); static boolean isWindows(); static boolean is1_7OrLater(); static boolean is1_7(); static boolean is1_8(); static int buildNumber(); static char windowsPathSeparator(); static TimeKeeper timer(); static long time(); static boolean inContainer(); static Object contextToHold(); static String sysPropMultipleKeys(String... keys); static String sysProp(String key); static String sysPropDefaultNull(String key); static String sysProp(String key, Object defaultValue); static boolean sysPropBoolean(String key); static boolean sysProp(String key, boolean defaultValue); static int sysPropInt(String key); static int sysProp(String key, int defaultValue); static File sysProp(String key, File defaultValue); static Path sysProp(String key, Path defaultValue); static int sysPropLong(String key); static long sysProp(String key, long defaultValue); static short sysPropShort(String key); static short sysProp(String key, short defaultValue); static byte sysPropByte(String key); static byte sysProp(String key, byte defaultValue); static BigDecimal sysPropBigDecimal(String key); static BigDecimal sysPropBigDecima(String key, BigDecimal defaultValue); static BigInteger sysPropBigInteger(String key); static BigInteger sysPropBigInteger(String key, BigInteger defaultValue); static T sysPropEnum(Class<T> cls, String key); static T sysProp(Class<T> cls, String key, T defaultValue); static String putSysProp(String key, Object value); static boolean hasSysProp(String propertyName); static void sleep(long duration); static int availableProcessors(); static long freeMemory(); static long totalMemory(); static long maxMemory(); static List<GarbageCollectorMXBean> gc(); static double loadAverage(); static long maxFileDescriptorCount(); static long openFileDescriptorCount(); static long committedVirtualMemorySize(); static long totalSwapSpaceSize(); static long freeSwapSpaceSize(); static long processCpuTime(); static long freePhysicalMemorySize(); static long totalPhysicalMemorySize(); static double systemCpuLoad(); static double processCpuLoad(); static long uptime(); static long startTime(); static int pendingFinalizationCount(); static MemoryUsage heapMemoryUsage(); static MemoryUsage nonHeapMemoryUsage(); static int threadPeakCount(); static int threadCount(); static long threadsStarted(); static long threadCPUTime(); static long threadUserTime(); static int threadDaemonCount(); static T loadFromFileLocation(Class<T> clazz, String... fileLocations); static ConcurrentHashMap <Object, Object> systemProperties; static ConcurrentHashMap <String, String> env; final static Object DEFAULT_NULL_NOT_EMPTY; }### Answer:
@Test public void testSysProp() throws Exception { String str = Sys.sysProp("KEY_SOME_VALUE", "/etc/foo"); Str.equalsOrDie("/etc/foo", str); }
@Test public void testSysPropNullDefault() throws Exception { String str = Sys.sysProp("KEY_SOME_VALUE", (String)null); Str.equalsOrDie("", str); }