JAVA_Home should be right but still shows "Note Java 8 can still be used in your own projects"

Describe the bug

I think my Java setup in my Visual Studio Code should be right. But this extension still show me this:

Spring Tools Language Server requires Java 11 or higher to be launched. Current Java /usr/lib/jvm/java-8-openjdk-amd64/bin/java. (Note Java 8 can still be used in your own projects. Java 11 is only required to launch the Spring Tools Language Server process)

Source: Spring Boot Tools (Extension)

To Reproduce

1. Initialize a Spring Boot project using this:

   https://start.spring.io/#!type=maven-project&language=java&platformVersion=2.5.3&packaging=jar&jvmVersion=11&groupId=com.example&artifactId=demo&name=demo&description=Demo%20project%20for%20Spring%20Boot&packageName=com.example.demo&dependencies=lombok,web
   

2. Use `Remote-SSH: Connect to Host…’ open Spring Boot project

3. Open MAVEN view in EXPLORER, expand demo node, click the + sign in the Dependencies noe

4. Search for spring-boot-starter-validation, choose the org.springframework.boot one.

5. The VSCode will show this message immediately.

   

6. My JAVA_HOME should be right.

   

7. The VSCode setting is empty.

   

Sample

Here is my sample project:

https://github.com/doggy8088/spring-boot-demo

[martinlippert]

The error message that you mentioned above looks like the Spring Boot Tools extension is picking up a JDK8 to run the language server process (a tooling-internal process, not related to your projects), but it needs JDK11. I don’t exactly know why the JDK8 is selected instead of the JDK11 that you have in your JAVA_HOME environment variable… 😦

In case this problem persists, you can specify which JDK the Spring Boot tools should use internally (again, just internally, not for your project) via the settings:

"spring-boot.ls.java.home": "/usr/lib/jvm/java-11-openjdk-amd64/bin/java"

(or whatever the right path to the Java executable of your JDK11 install is)

[martinlippert]

This is covered by the latest changes, I think, which is looking at the STS4 specific property first and tries java.home next, if the STS4 property is not set or not set to an existing JDK.