JSON 5

The Json5Serializer class can be used to serialized POJOs into JSON 5 notation.

JSON 5 is similar to JSON except for the following:

JSON attributes are only quoted when necessary.
Uses single-quotes for quoting.

Examples

// Some free-form JSON.
JsonMap map = JsonMap.of(
    "foo", "x1",
    "_bar", "x2",
    " baz ", "x3",
    "123", "x4",
    "return", "x5",
    "", "x6"
);

// Serialized to standard JSON
{
    "foo": "x1",
    "_bar": "x2",
    " baz ": "x3",
    "123": "x4",
    "return": "x5",
    "": "x6"
}

// Serialized to JSON5
{
    foo: 'x1',
    _bar: 'x2',
    ' baz ': 'x3',  // Quoted due to embedded spaces.
    '123': 'x4',    // Quoted to prevent confusion with number.
    'return': 'x5', // Quoted because it's a keyword.
    '': 'x6'        // Quoted because it's an empty string.
}

The advantage to JSON 5 is you can represent it in a Java String in minimal form with minimal escaping. This is particularly useful in cases such as unit testing where you can easily validate POJOs by simplifying them to JSON 5 and do a simple string comparison.

WriterSerializer serializer = Json5Serializer.DEFAULT;
assertEquals("{foo:'bar',baz:123}", serializer.toString(myPojo));

Readable output — the `Json5R` variant marshaller

For indented, multi-line JSON5 output, use the dedicated Json5R variant marshaller (backed by Json5Serializer.DEFAULT_READABLE). It is a first-class Json5 facade, so it exposes the same static of(...) / to(...) shortcut surface as Json5 itself:

// Compact (default):
String compact = Json5.of(myPojo);    // {foo:'bar',baz:123}

// Readable (indented, multi-line):
String pretty = Json5R.of(myPojo);

(This replaces the former Json5.DEFAULT_READABLE constant, removed in 10.0.0.)

Readable output — the Json5R variant marshaller​

Readable output — the `Json5R` variant marshaller