### Question:
Utilities { public static boolean isNullOrEmptyString(final String value) { return value == null || value.trim().isEmpty(); } private  Utilities(); static boolean isNullOrEmptyString(final String value); static String createRandomAlphanumeric(final int length); static String createAlphanumericHash(final String str, final int length); static void generateInvocationIdIfNecessary(final TraceeBackend backend); static void generateSessionIdIfNecessary(final TraceeBackend backend, final String sessionId); static final Charset CHARSET_UTF8; }### Answer:
@Test public void testIsNullOrEmptyString() { assertThat(Utilities.isNullOrEmptyString(null), is(true)); assertThat(Utilities.isNullOrEmptyString(""), is(true)); assertThat(Utilities.isNullOrEmptyString(" "), is(true)); assertThat(Utilities.isNullOrEmptyString(" \n\t"), is(true)); assertThat(Utilities.isNullOrEmptyString("a"), is(false)); }