char[] b2 = buffer.toCharArray();
assertNotNull(b2);
assertEquals(4, b2.length);
for (int i = 0; i < tmp.length; i++) {
assertEquals(tmp[i], b2[i]);
assertEquals(tmp[i], buffer.charAt(i));
}
assertEquals("1234", buffer.toString());
buffer.clear();
assertEquals(16, buffer.capacity());