### Question:
ByteArrayBuilder { public void reset() { if (this.charsetEncoder != null) { this.charsetEncoder.reset(); } if (this.buffer != null) { this.buffer.clear(); } } ByteArrayBuilder();  ByteArrayBuilder(final int initialCapacity); int capacity(); void ensureFreeCapacity(final int freeCapacity); ByteArrayBuilder charset(final Charset charset); ByteArrayBuilder append(final byte[] b, final int off, final int len); ByteArrayBuilder append(final byte[] b); ByteArrayBuilder append(final CharBuffer charBuffer); ByteArrayBuilder append(final char[] b, final int off, final int len); ByteArrayBuilder append(final char[] b); ByteArrayBuilder append(final String s); ByteBuffer toByteBuffer(); byte[] toByteArray(); void reset(); @Override String toString();  }### Answer:
@Test public void testReset() throws Exception { final ByteArrayBuilder buffer = new ByteArrayBuilder(); buffer.append("abcd"); buffer.append("e"); buffer.append("f"); final byte[] bytes1 = buffer.toByteArray(); Assert.assertNotNull(bytes1); Assert.assertEquals("abcdef", new String(bytes1, StandardCharsets.US_ASCII)); buffer.reset(); final byte[] bytes2 = buffer.toByteArray(); Assert.assertNotNull(bytes2); Assert.assertEquals("", new String(bytes2, StandardCharsets.US_ASCII)); }