### Question:
NullPrefixer implements Prefixer { @Override public void encodeLength(int length, byte[] b) {} private  NullPrefixer(); @Override void encodeLength(int length, byte[] b); @Override int decodeLength(byte[] b, int offset); @Override int getPackedLength(); static final NullPrefixer INSTANCE; }### Answer:
@Test public void testEncodeLength() throws Throwable { NullPrefixer INSTANCE = NullPrefixer.INSTANCE; byte[] b = new byte[2]; INSTANCE.encodeLength(100, b); assertEquals(0, INSTANCE.getPackedLength(), "INSTANCE.getPackedLength()"); }