### Question:
Strings { public static String toCamel(String snake) { if (Strings.isBlank(snake)) return ""; String[] fragments = snake.split("_"); StringBuilder cameled = new StringBuilder(); for (int i = 0; i < fragments.length; i++) { cameled.append(i == 0 ? fragments[i].toLowerCase() : Beans.capitalize(fragments[i].toLowerCase())); } return cameled.toString(); } private  Strings(); static String substitute(String string, Map<String, ? extends Object> replace); static String substitute(String string, Map<String, ? extends Object> replace, Locale locale); static String findPlaceHolder(String string); static String clearEscapedPlaceHolder(String dirty); static T proper(T returnIfNotEmpty, T alternative); static String toCamel(String snake); static String toSnake(String camel); static String join(T... joinees); static String joinBy(String separator, T... joinees); static String join(List<T> joinees); static String joinBy(String separator, List<T> joinees); static boolean isBlank(CharSequence suspect); static boolean containBlank(CharSequence suspect); static String removeBlanks(CharSequence target); static boolean isEmpty(CharSequence suspect); static boolean isEmpty(CharSequence suspect, boolean removeBlanks); static String reverse(String reversee); static String trim(String target); static String[] split(String regex, String target); static boolean equalsIgnoreCase(String source, String destination); static boolean startsWith(String text, String prefix); static boolean startsWith(String text, String prefix, boolean textCompare); static boolean endsWith(String text, String prefix); static boolean endsWith(String text, String prefix, boolean textCompare); static String escapeHTML(CharSequence html); static String escapeRegex(CharSequence text);  }### Answer:
@Test public void toCamelテスト() { assertThat(Strings.toCamel(""), is("")); assertThat(Strings.toCamel("A_B"), is("aB")); assertThat(Strings.toCamel("AB"), is("ab")); assertThat(Strings.toCamel("ABC"), is("abc")); assertThat(Strings.toCamel("A_BC"), is("aBc")); assertThat(Strings.toCamel("AB_C"), is("abC")); assertThat(Strings.toCamel("AB_CD"), is("abCd")); assertThat(Strings.toCamel("0B"), is("0b")); assertThat(Strings.toCamel("0_B"), is("0B")); assertThat(Strings.toCamel("A1"), is("a1")); }