StringUtils { public static String uncapitalize(String expression) { return Objects.requireNonNull(expression, "String value cannot be null").isEmpty() ? expression : expression.substring(0, 1).toLowerCase() + expression.substring(1); } private  StringUtils(); static String uncapitalize(String expression); static String capitalize(String expression);  }
@Test(expectedExceptions = NullPointerException.class, expectedExceptionsMessageRegExp = "String value cannot be null") public void testUncapitalizingNullValue() { StringUtils.uncapitalize(null); }
@Test public void testUncapitalizingEmptyString() { assertThat(StringUtils.uncapitalize(""), is("")); }
@Test public void testUncapitalizingUncapitalizedString() { assertThat(StringUtils.uncapitalize("hello"), is("hello")); }
@Test public void testUncapitalizingCapitalizedString() { assertThat(StringUtils.uncapitalize("Hello"), is("hello")); }