JSON Java 8 LocalDateTime format in Spring Boot

update: Spring Boot 2.x doesn't require this configuration anymore. I've written a more up to date answer here.

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(This is the way of doing it before Spring Boot 2.x, it might be useful for people working on an older version of Spring Boot)

I finally found here how to do it. To fix it, I needed another dependency:

compile("com.fasterxml.jackson.datatype:jackson-datatype-jsr310:2.4.0")

By including this dependency, Spring will automatically register a converter for it, as described here. After that, you need to add the following to application.properties:

spring.jackson.serialization.write_dates_as_timestamps=false

This will ensure that a correct converter is used, and dates will be printed in the format of 2016-03-16T13:56:39.492

Annotations are only needed in case you want to change the date format.

I added the com.fasterxml.jackson.datatype:jackson-datatype-jsr310:2.6.1 dependency and started to get the date in the following format:

"birthDate": [
    2016,
    1,
    25,
    21,
    34,
    55
  ]

which is not what I wanted but I was getting closer. I then added the following

spring.jackson.serialization.write_dates_as_timestamps=false

to application.properties file which gave me the correct format that I needed.

"birthDate": "2016-01-25T21:34:55"