### Question:
TokenUtil { public static String sanitizeTokenString(final String tokenString) { return tokenString.replaceAll("[^a-fA-F0-9]", ""); } private  TokenUtil(); static String sanitizeTokenString(final String tokenString);  }### Answer:
@Test void testSanitizeTokenString() { assertEquals("ffff1234", TokenUtil.sanitizeTokenString("<ffff 1234>")); }
@SuppressWarnings({"ResultOfMethodCallIgnored", "ConstantConditions"}) @Test void testSanitizeNullTokenString() { assertThrows(NullPointerException.class, () -> TokenUtil.sanitizeTokenString(null)); }