### Question:
DataUtil { static String mimeBoundary() { final StringBuilder mime = StringUtil.borrowBuilder(); final Random rand = new Random(); for (int i = 0; i < boundaryLength; i++) { mime.append(mimeBoundaryChars[rand.nextInt(mimeBoundaryChars.length)]); } return StringUtil.releaseBuilder(mime); } private  DataUtil(); static Document load(File in, String charsetName, String baseUri); static Document load(InputStream in, String charsetName, String baseUri); static Document load(InputStream in, String charsetName, String baseUri, Parser parser); static ByteBuffer readToByteBuffer(InputStream inStream, int maxSize);  }### Answer:
@Test public void generatesMimeBoundaries() { String m1 = DataUtil.mimeBoundary(); String m2 = DataUtil.mimeBoundary(); assertEquals(DataUtil.boundaryLength, m1.length()); assertEquals(DataUtil.boundaryLength, m2.length()); assertNotSame(m1, m2); }