Who can help me ? Ehcache 3.4.0 Custom Serializers get Error : Method threw 'org.ehcache.spi.serialization.SerializerException' exception. Cannot evaluate org.ehcache.impl.internal.store.offheap.LazyOffHeapValueHolder.toString()

hello , I see the document (http://www.ehcache.org/blog/2016/05/12/ehcache3-serializers.html#disqus_thread) and then write example， but invoke ‘cache.getAll()’ get null and debug get error : Method threw ‘org.ehcache.spi.serialization.SerializerException’ exception. Cannot evaluate org.ehcache.impl.internal.store.offheap.LazyOffHeapValueHolder.toString()

invoke “cache.get()” can get correct value .

public class SerializerTest {
    CacheManager dataCacheManager = null;
    Cache        myCache          = null;

    @Test
    public void test() {

        try {

            CacheConfiguration<String, TestVO> dataCacheConfig = CacheConfigurationBuilder
                .newCacheConfigurationBuilder(
                    String.class,
                    TestVO.class,
                    ResourcePoolsBuilder.newResourcePoolsBuilder().heap(10)
                        .offheap(10, MemoryUnit.MB)).withExpiry(Expirations.noExpiration())
                .withValueSerializer(new HessianSerializer()).build();
            dataCacheManager = CacheManagerBuilder.newCacheManagerBuilder()
                .withCache("Test", dataCacheConfig).build(true);
            myCache = dataCacheManager.getCache("Test", String.class, TestVO.class);

            for (int i = 0; i < 10; ++i) {
                TestVO testVO = new TestVO("k" + i, "v" + i);
                myCache.put("key" + i, testVO);
            }
            System.out.println("get key0=" + myCache.get("key0"));
            System.out.println("get key1=" + myCache.get("key1"));

            // get null , debug get error : Method threw 'org.ehcache.spi.serialization.SerializerException' exception. Cannot evaluate org.ehcache.impl.internal.store.offheap.LazyOffHeapValueHolder.toString()
            System.out.println("getAll=" + myCache.getAll(Sets.newHashSet("key0", "key1")));

        } catch (Throwable tr) {
            System.out.println("ehcache error : " + tr);
            Assert.assertTrue(false);
        }
    }

    class HessianSerializer implements Serializer<TestVO> {

        private final HessianSerUtils HESSIAN_SER_UTILS = new HessianSerUtils();

        public HessianSerializer(ClassLoader loader) {
            //no-op
        }

        public HessianSerializer() {
            //no-op
        }

        @Override
        public ByteBuffer serialize(TestVO object) throws SerializerException {

            try {
                return ByteBuffer.wrap(HESSIAN_SER_UTILS.serialize(object));
            } catch (IOException e) {
                e.printStackTrace();
            }
            return null;
        }

        @Override
        public TestVO read(ByteBuffer binary) throws ClassNotFoundException, SerializerException {
            try {
                return (TestVO) HESSIAN_SER_UTILS.deserialize(binary.array());
            } catch (IOException e) {
                e.printStackTrace();
            }
            return null;
        }

        @Override
        public boolean equals(TestVO object, ByteBuffer binary) throws ClassNotFoundException,
                                                               SerializerException {
            return object.equals(read(binary));
        }
    }
}

debug find invoke “cache.put()” , the data in cache is :

I’m sorry , My English is very poor. but who can help me ? why ?