Strings { @Deprecated public static String emptyToNull(String string) { return isNullOrEmpty(string) ? null : string; } private  Strings(); @Deprecated static String nullToEmpty(String string); @Deprecated static String emptyToNull(String string); @Deprecated static boolean isNullOrEmpty(String string); @Deprecated static String join(String delimiter, String... parts); @Deprecated static String[] split(String raw, char ch); @Deprecated static String longestCommonPrefix(String... input);  }
@Test public void testEmptyToNull() { assertNull(Strings.emptyToNull(null)); assertNull(Strings.emptyToNull("")); assertEquals(Strings.emptyToNull("a"), "a"); }