### Question:
Strings { public static String firstNotBlank(final String... strings) { for (final String s : strings) { if (StringUtils.isNotBlank(s)) { return s; } } return null; } private  Strings(); static String firstNotBlank(final String... strings); static String removeWhitespaces(final String string); static final String TAB; static final String DOT; static final String EQ; static final String SLASH; static final String DASH; static final String _SCORE; static final String COLON; }### Answer:
@Test public void firstNotBlank() { assertNull(Strings.firstNotBlank()); assertNull(Strings.firstNotBlank(EMPTY)); assertNull(Strings.firstNotBlank((String)null)); assertNull(Strings.firstNotBlank(" ")); assertNull(Strings.firstNotBlank("\t")); assertNull(Strings.firstNotBlank("\n")); assertNull(Strings.firstNotBlank(EMPTY, "\n", "\t", "\n", null, " ")); assertEquals(X, Strings.firstNotBlank(X)); assertEquals(X, Strings.firstNotBlank(X, Y)); assertEquals(X, Strings.firstNotBlank(X, EMPTY)); assertEquals(X, Strings.firstNotBlank(X, " ")); assertEquals(X, Strings.firstNotBlank(X)); }