0
# ObjectMapper Factory
1

2
The `Jackson` utility class provides factory methods for creating pre-configured `ObjectMapper` instances optimized for Dropwizard applications.
3

4
## Static Factory Methods
5

6
### newObjectMapper()
7

8
Creates a new ObjectMapper with comprehensive Dropwizard configuration including all modules and optimizations.
9

10
```java { .api }
11
public static ObjectMapper newObjectMapper()
12
```
13

14
**Returns**: Fully configured `ObjectMapper` instance
15

16
**Configuration includes**:
17
- Guava module for Guava collections support
18
- GuavaExtrasModule for CacheBuilderSpec serialization
19
- CaffeineModule for CaffeineSpec serialization
20
- FuzzyEnumModule for permissive enum deserialization
21
- ParameterNamesModule for constructor parameter name preservation
22
- Jdk8Module for Optional and Stream support
23
- JavaTimeModule for JSR-310 time types
24
- Performance module (Afterburner or Blackbird)
25
- AnnotationSensitivePropertyNamingStrategy for snake_case support
26
- DiscoverableSubtypeResolver for polymorphic configurations
27
- Disables FAIL_ON_UNKNOWN_PROPERTIES
28

29
**Usage Example**:
30
```java
31
ObjectMapper mapper = Jackson.newObjectMapper();
32

33
// The mapper is now ready for production use with all optimizations
34
String json = mapper.writeValueAsString(complexObject);
35
MyClass result = mapper.readValue(json, MyClass.class);
36
```
37

38
### newObjectMapper(JsonFactory)
39

40
Creates a new ObjectMapper with a custom JsonFactory and full Dropwizard configuration.
41

42
```java { .api }
43
public static ObjectMapper newObjectMapper(JsonFactory jsonFactory)
44
```
45

46
**Parameters**:
47
- `jsonFactory` (`JsonFactory`, nullable): Custom JsonFactory instance to use
48

49
**Returns**: Fully configured `ObjectMapper` instance using the provided JsonFactory
50

51
**Usage Example**:
52
```java
53
// Create ObjectMapper with custom JsonFactory for YAML processing
54
YAMLFactory yamlFactory = new YAMLFactory();
55
ObjectMapper yamlMapper = Jackson.newObjectMapper(yamlFactory);
56

57
// Or with custom JSON factory settings
58
JsonFactory customFactory = new JsonFactory()
59
    .enable(JsonParser.Feature.ALLOW_COMMENTS);
60
ObjectMapper mapper = Jackson.newObjectMapper(customFactory);
61
```
62

63
### newMinimalObjectMapper()
64

65
Creates a minimal ObjectMapper with only essential Dropwizard configuration for less aggressive processing.
66

67
```java { .api }
68
public static ObjectMapper newMinimalObjectMapper()
69
```
70

71
**Returns**: Minimally configured `ObjectMapper` instance
72

73
**Configuration includes**:
74
- GuavaModule for basic Guava collections support
75
- DiscoverableSubtypeResolver for polymorphic configurations
76
- Disables FAIL_ON_UNKNOWN_PROPERTIES
77

78
**Usage Example**:
79
```java
80
// Use when the full configuration is too aggressive for your use case
81
ObjectMapper minimalMapper = Jackson.newMinimalObjectMapper();
82

83
// Still provides essential Dropwizard functionality
84
String json = minimalMapper.writeValueAsString(simpleObject);
85
```
86

87
## Configuration Details
88

89
### Automatic Module Discovery
90

91
The factory methods automatically discover and register Jackson modules available on the classpath:
92

93
- **Afterburner Module**: High-performance bytecode generation (preferred)
94
- **Blackbird Module**: Fallback performance enhancement when Afterburner unavailable
95

96
### Property Handling
97

98
- **Unknown Properties**: Ignored by default (FAIL_ON_UNKNOWN_PROPERTIES disabled)
99
- **Naming Strategy**: Supports both camelCase and snake_case via `@JsonSnakeCase` annotation
100
- **Parameter Names**: Preserved in JSON for constructor parameters
101

102
### Type Support
103

104
- **Java 8 Types**: Optional, Stream, LocalDate, LocalDateTime, Instant, etc.
105
- **Guava Collections**: ImmutableList, ImmutableMap, Multimap, etc.
106
- **Cache Specifications**: CaffeineSpec and CacheBuilderSpec serialization
107
- **Enums**: Fuzzy matching (case-insensitive, handles dashes/periods)