Strings { public static String lowercaseFirstLetter(String string) { if (string == null || string.length() == 0) { return string; } else { return string.substring(0, 1).toLowerCase() + string.substring(1); } } private  Strings(); static String toCsv(List<String> src); static String join(List<String> src, String delimiter); static String capitaliseFirstLetter(String string); static String lowercaseFirstLetter(String string); static String zeros(int n); static String repeat(char value, int n); static boolean isEmpty(String s);  }
@Test public void testLowercaseFirstLetter() { assertThat(Strings.lowercaseFirstLetter(""), is("")); assertThat(Strings.lowercaseFirstLetter("A"), is("a")); assertThat(Strings.lowercaseFirstLetter("AA"), is("aA")); assertThat(Strings.lowercaseFirstLetter("a"), is("a")); assertThat(Strings.lowercaseFirstLetter("aB"), is("aB")); }