### Question:
BigIntegerAccessor implements PropertyAccessor<BigInteger> { @Override public BigInteger fromString(Class targetClass, String s) { return s != null ? new BigInteger(s) : null; }  @Override BigInteger fromBytes(Class targetClass, byte[] b); @Override byte[] toBytes(Object object); @Override String toString(Object object); @Override BigInteger fromString(Class targetClass, String s); @Override BigInteger getCopy(Object object); BigInteger getInstance(Class<?> clazz);  }### Answer:
@Test public void testFromString() { Assert.assertNull(accessor.fromString(BigInteger.class, null)); BigInteger v1 = new BigInteger("1111111111"); String s = v1.toString(); BigInteger v2 = accessor.fromString(BigInteger.class, s); Assert.assertEquals(v1, v2); }