### Question:
StringUtils { public static String deleteXmlWhitespace(String string) { return XML_WHITESPACE.matcher(string).replaceAll(""); }  static CharSequence escapeForXml(CharSequence input); static CharSequence escapeForXmlAttribute(CharSequence input); static CharSequence escapeForXmlAttributeApos(CharSequence input); static CharSequence escapeForXmlText(CharSequence input); @Deprecated static synchronized String hash(String data); static String encodeHex(byte[] bytes); static byte[] toUtf8Bytes(String string); static String insecureRandomString(int length); static String secureOnlineAttackSafeRandomString(); static String secureUniqueRandomString(); static String secureOfflineAttackSafeRandomString(); static String randomString(final int length); static String randomString(final int length, Random random); static boolean isNotEmpty(CharSequence cs); static boolean isNullOrEmpty(CharSequence cs); static boolean isNotEmpty(CharSequence... css); static boolean isNullOrEmpty(CharSequence... css); static boolean isNullOrNotEmpty(CharSequence cs); static boolean isEmpty(CharSequence cs); static String collectionToString(Collection<? extends Object> collection); static StringBuilder toStringBuilder(Collection<? extends Object> collection, String delimiter); static void appendTo(Collection<? extends Object> collection, StringBuilder sb); static void appendTo(Collection<O> collection, StringBuilder sb,
                    Consumer<O> appendFunction); static void appendTo(Collection<? extends Object> collection, String delimiter, StringBuilder sb); static void appendTo(Collection<O> collection, String delimiter, StringBuilder sb,
                    Consumer<O> appendFunction); static String returnIfNotEmptyTrimmed(String string); static boolean nullSafeCharSequenceEquals(CharSequence csOne, CharSequence csTwo); static int nullSafeCharSequenceComparator(CharSequence csOne, CharSequence csTwo); @Deprecated static CS requireNotNullOrEmpty(CS cs, String message); static CS requireNotNullNorEmpty(CS cs, String message); static CS requireNullOrNotEmpty(CS cs, String message); static String maybeToString(CharSequence cs); static String deleteXmlWhitespace(String string); static Appendable appendHeading(Appendable appendable, String heading); static Appendable appendHeading(Appendable appendable, String heading, char underlineChar); static List<String> splitLinesPortable(String input); static final String MD5; static final String SHA1; @Deprecated
    static final String UTF8; @Deprecated
    static final String USASCII; static final String QUOTE_ENCODE; static final String APOS_ENCODE; static final String AMP_ENCODE; static final String LT_ENCODE; static final String GT_ENCODE; static final char[] HEX_CHARS; static final String UNAMBIGUOUS_NUMBERS_AND_LETTERS_STRING; static final String PORTABLE_NEWLINE_REGEX; }### Answer:
@Test public void testeDeleteXmlWhitespace() { String noWhitespace = StringUtils.deleteXmlWhitespace(" foo\nbar "); assertEquals("foobar", noWhitespace); noWhitespace = StringUtils.deleteXmlWhitespace(" \tbaz\rbarz\t "); assertEquals("bazbarz", noWhitespace); noWhitespace = StringUtils.deleteXmlWhitespace("SNAFU"); assertEquals("SNAFU", noWhitespace); }