Change Java Runtime Version in Intellij Idea-CodePudding

I am deploying a server built with ktor to Heroku, but when I run command heroku open I receive Application error

Following is shown in the logs

Exception in thread "main" java.lang.UnsupportedClassVersionError:com/zaxxer/hikari/HikariConfig has been compiled by a more recent version of the Java Runtime (class file version 55.0), this version of the Java Runtime only recognizes class file versions up to 52.0

When I run heroku run java -version I receive this

openjdk version "1.8.0_312-heroku"
OpenJDK Runtime Environment (build 1.8.0_312-heroku-b05)
OpenJDK 64-Bit Server VM (build 25.312-b05, mixed mode)

How can I change the Java Runtime version in Intellij idea

CodePudding user response：

You need to change the Java version on Heroku where you deploy the application (by default Heroku provides Java 8, as you correctly verified).

In the project root place a file system.properties which contains:

java.runtime.version=11

CodePudding user response：

You need to change not the java Runtime version of IDEA, but the JDK you use to build the project to a lower version. See Project SDK.