### Question:
StringUtil { public static String fromSnakeCaseToCamelCase(String text) { if (isNullOrEmpty(text)) { return text; } String[] array = text.split("_"); if (array.length == 0) { return ""; } StringBuilder result = new StringBuilder(); result.append(array[0].toLowerCase()); for (int i = 1; i < array.length; i++) { String s = capitalize(array[i].toLowerCase()); result.append(s); } return result.toString(); }  @SuppressWarnings("CStyleArrayDeclaration") static String capitalize(String text); @SuppressWarnings("CStyleArrayDeclaration") static String decapitalize(String text); static String fromSnakeCaseToCamelCase(String text); static String fromCamelCaseToSnakeCase(String text); static String fromCamelCaseToSnakeCaseWithLenient(String text); static boolean isWhitespace(String text); static String trimWhitespace(String text);  }### Answer:
@Test public void testFromSnakeCaseToCamelCase() { assertEquals("aaaBbbCcc", StringUtil.fromSnakeCaseToCamelCase("AAA_BBB_CCC")); assertEquals("aaaBbbCcc", StringUtil.fromSnakeCaseToCamelCase("aaa_bbb_ccc")); assertEquals("abc", StringUtil.fromSnakeCaseToCamelCase("ABC")); assertEquals("abc", StringUtil.fromSnakeCaseToCamelCase("abc")); }