There’s a number of posts (e.g. here) talking about the official Java docker images being on the large side – in Docker terms, the standard images at > 600MB before you even build your image containing you app are … pretty big.
Suggestions are to use a smaller image as a starting point, like Alpine Linux. It looks like at some point the official Java images have been updates to include a number of Alpine based images too.
Pulling down an OpenJDK 8 image, java:openjdk-8-jdk and then java:openjdk-8-alpine, there’s a massive size difference between the size of the two:
If you’re planning on running something lightweight like a Spring Boot app, looks like the provided Alpine images are a good starting point.