### Question:
HeaderUtil { public static String stripHeaderValue(String value) { StringBuilder builder = new StringBuilder(value.length()); boolean modified = false; for (int i = 0, length = value.length(); i < length; i++) { char c = value.charAt(i); if ((c > '\u001f' && c < '\u007f') || c == '\t' ) { builder.append(c); } else { modified = true; } } return modified ? builder.toString() : value; }  static String stripHeaderName(String name); static String stripHeaderValue(String value);  }### Answer:
@Test public void valueStripKeepsLetters() { assertEquals(ALPHABET_TEST, HeaderUtil.stripHeaderValue(ALPHABET_TEST)); }
@Test public void valueStripKeepsNumbers() { assertEquals(NUMBERS_TEST, HeaderUtil.stripHeaderValue(NUMBERS_TEST)); }
@Test public void valueStripKeepsSpecials() { assertEquals(SPECIALS_TEST, HeaderUtil.stripHeaderValue(SPECIALS_TEST)); }
@Test public void valueStripKeepsTabs() { assertEquals(TABULATION_TEST, HeaderUtil.stripHeaderValue(TABULATION_TEST)); }
@Test public void valueStripRemovesExtraSymbols() { assertEquals(BANNED_TEST_EXPECTED, HeaderUtil.stripHeaderValue(VALUE_BANNED_SYMBOLS_TEST)); }