package org.springframework.boot does not exist

You need add this dependency

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>

then it will work.

You have 0 compile dependencies, only test-compile dependencies defined, because you've commented out spring-boot-starter-data-jpa. Spring starter's pull other dependencies in (including other starters) to create everything needed at compile time. Un-comment the spring-boot-starter-data-jpa dependency, and/or re-evaulate what dependencies you actually want.

1) Close the project 2) Import the project again with auto-import checked

This worked for me. Maybe works for you too.