### Question:
Str { public static String compact( String str ) { return FastStringUtils.noCopyStringFromChars( Chr.compact( FastStringUtils.toCharArray(str) ) ); }  static int lengthOf( String str ); static String sliceOf( String str, int start ); static String sliceOf( String str, int start, int end ); static String endSliceOf( String str, int end ); static char atIndex( String str, int index ); static String atIndex( String str, int index, char c ); static int len( String str ); static String slc( String str, int start ); static String slc( String str, int start, int end ); static String slcEnd( String str, int end ); static char idx( String str, int index ); static String idx( String str, int index, char c ); static boolean in( char[] chars, String str ); static boolean in( char c, String str ); static boolean in( char c, int offset, String str ); static boolean in( char c, int offset, int end, String str ); static String add( String str, char c ); static String add( String str, String str2 ); static String add( String... strings ); static String addObjects( Object... objects ); static String compact( String str ); static String[] split( String str ); static String[] splitLines( String str ); static String[] splitComma( String str ); static String[] splitBySpace( String str ); static String[] splitByPipe( String str ); static String[] fromCharArrayOfArrayToStringArray( char[][] split ); static String upper( String str ); static String lower( String str ); static String camelCaseUpper( String in ); static String camelCaseLower( String in ); static String camelCase( String in ); static String camelCase( String inStr, boolean upper ); static boolean insideOf(String start, String inStr, String end); static String underBarCase( String inStr ); static void equalsOrDie(CharSequence a, CharSequence b); static void equalsOrDie(String a, String b); static String lpad( String inStr, int size, char fill ); static String lpad( String inStr, int size ); static String lpad( Object inStr, int size ); static String lpad( Object inStr); static String zfill( int num, int size ); static String rpad( String inStr, int size, char fill ); static String rpad( String inStr, int size); static String rpad( Object obj, int size); static String rpad( Object obj); static String rpad( Object obj, int size, char fill ); static String[] split( final String input,
                                  final char split ); static boolean in( String value, String str ); static String lines( String... lines ); static String linesConvertQuotes( String... lines ); static String join( char delim, String... args ); static String joinObjects( char delim, Object... args ); static String join( String... args ); static String joinCollection( char delim, List<?> args ); static String joinCollection( String delim, List<?> args ); static boolean isEmpty( String str ); static boolean isEmpty( Object str ); static String uncapitalize( String string ); static String toString(Object object, String defaultString); static String toString(Object object); static String str(Object str); static boolean startsWithItemInCollection(String name, Collection<String> startsWithList); static String readable(String s); static String quote(String s); static String singleQuote(String s); static String doubleQuote(String s); static String str(byte[] bytes); static String num(Number count); static void println(String message); static String sputl(Object... messages); static String sputs(Object... messages); static CharBuf sputl(CharBuf buf, Object... messages); static CharBuf sputs(CharBuf buf, Object... messages); static StringBuilder sputs(StringBuilder buf, Object... messages); static String toPrettyJson(Object object); static String toPrettyJsonWithTypes(Object object); final static String EMPTY_STRING; }### Answer:
@Test public void compactTest() { String letters = "ab\0\0\0\0\0\0c\0d\0\0e"; letters = compact( letters ); assertEquals( "abcde", letters ); }