These tests fail, demonstrating either a bug somewhere in the Jackson / Spring-Data-Redis stack, or a configuration problem within my code. It requires Lombok to run

gistfile1.txt

package com.mangofactory.example

import static org.hamcrest.CoreMatchers.notNullValue;
import static org.hamcrest.CoreMatchers.nullValue;
import static org.hamcrest.Matchers.contains;
import static org.hamcrest.Matchers.hasSize;
import static org.junit.Assert.assertThat;

import java.util.Collections;
import java.util.List;
import java.util.Map;

import lombok.Data;

import org.junit.Test;
import org.springframework.data.redis.hash.DecoratingStringHashMapper;
import org.springframework.data.redis.hash.JacksonHashMapper;

import com.google.common.collect.Lists;

public class JacksonSerializerTests {

  @Test
	public void nullLongIsHandledCorrectly()
	{
		DecoratingStringHashMapper<EntityWithId> mapper = mapperOf(EntityWithId.class);
		EntityWithId entity = new EntityWithId();
	
		// Encode & decode
		Map<String, String> hash = mapper.toHash(entity);
		EntityWithId decoded = mapper.fromHash(hash);
		
		assertThat(decoded, notNullValue());
		assertThat(decoded.getId(), nullValue());
	}
	
	@Test
	public void listOfEnumsDecodedCorrectly()
	{
		DecoratingStringHashMapper<EntityWithListOfEnums> mapper = mapperOf(EntityWithListOfEnums.class);
		EntityWithListOfEnums entity = new EntityWithListOfEnums();
	
		// Encode & decode
		Map<String, String> hash = mapper.toHash(entity);
		EntityWithListOfEnums decoded = mapper.fromHash(hash);
		
		assertThat(decoded, notNullValue());
		assertThat(decoded.getRoles(), hasSize(1));
		assertThat(decoded.getRoles(), contains(UserRole.USER));
	}
	
	@Test
	public void emptyListDecodedCorreclty()
	{
		DecoratingStringHashMapper<EntityWithListOfEnums> mapper = mapperOf(EntityWithListOfEnums.class);
		EntityWithListOfEnums entity = new EntityWithListOfEnums();
		List<UserRole> roles = Collections.emptyList();
		entity.setRoles(roles);
		
		// Encode & decode
		Map<String, String> hash = mapper.toHash(entity);
		EntityWithListOfEnums decoded = mapper.fromHash(hash);
		
		assertThat(decoded, notNullValue());
		assertThat(decoded.getRoles(), notNullValue());
		assertThat(decoded.getRoles(), hasSize(0));
	}
	
	@Test
	public void listOfStringsDecodedCorrectly()
	{
		DecoratingStringHashMapper<EntityWithListOfStrings> mapper = mapperOf(EntityWithListOfStrings.class);
		EntityWithListOfStrings entity = new EntityWithListOfStrings();
	
		// Encode & decode
		Map<String, String> hash = mapper.toHash(entity);
		EntityWithListOfStrings decoded = mapper.fromHash(hash);
		
		assertThat(decoded, notNullValue());
		assertThat(decoded.getRoles(), hasSize(1));
		assertThat(decoded.getRoles(), contains("Hello","World"));
	}
	@Test
	public void emptyListOfStringsDecodedCorrectly()
	{
		DecoratingStringHashMapper<EntityWithListOfStrings> mapper = mapperOf(EntityWithListOfStrings.class);
		EntityWithListOfStrings entity = new EntityWithListOfStrings();
		List<String> roles = Collections.emptyList();
		entity.setRoles(roles);
		
		// Encode & decode
		Map<String, String> hash = mapper.toHash(entity);
		EntityWithListOfStrings decoded = mapper.fromHash(hash);
		
		assertThat(decoded, notNullValue());
		assertThat(decoded.getRoles(), hasSize(1));
		assertThat(decoded.getRoles(), contains("Hello","World"));
	}
	@Data
	public static class EntityWithId
	{
		Long id;
		String otherField = "Hello"; // so there's something to serialize
	}
	@Data
	public static class EntityWithListOfEnums
	{
		List<UserRole> roles = Lists.newArrayList(UserRole.USER);
	}
	@Data
	public static class EntityWithListOfStrings
	{
		List<String> roles = Lists.newArrayList("Hello","World");
	}
	public enum UserRole
	{
		USER,ADMIN;
	}
	
	private <T> DecoratingStringHashMapper<T> mapperOf(Class<T> clazz)
	{
		return new DecoratingStringHashMapper<T>(new JacksonHashMapper<T>(clazz));
	}
}