@Test public void testBigNumber() { SimpleObj2 s = new SimpleObj2(); s.setBigDecimal(new BigDecimal("-3.34")); s.setBigInteger(new BigInteger("-4")); String json = Json.toJson(s); System.out.println(json); SimpleObj2 s2 = Json.toObject(json, SimpleObj2.class); Assert.assertThat(s2.getBigDecimal(), is(new BigDecimal("-3.34"))); Assert.assertThat(s2.getBigInteger(), is(new BigInteger("-4"))); }