Grails 4.0 no Linux

Bom, eu ainda tento usar o Grails, e gosto do que vejo, sendo que fui tentar reinstalar agora para tentar voltar aos estudos e estou tendo o seguinte problema ao tentar rodar o projeto:

General error during semantic analysis: Unsupported class file major version 57

java.lang.IllegalArgumentException: Unsupported class file major version 57

$ java -version
java version “13.0.2” 2020-01-14
Java™ SE Runtime Environment (build 13.0.2+8)
Java HotSpot™ 64-Bit Server VM (build 13.0.2+8, mixed mode, sharing)

$ grails -version
WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by org.codehaus.groovy.vmplugin.v7.Java7$1 (file:/home/eduardocasa/.sdkman/candidates/grails/4.0.2/lib/org.codehaus.groovy/groovy/jars/groovy-2.5.6.jar) to constructor java.lang.invoke.MethodHandles$Lookup(java.lang.Class,int)
WARNING: Please consider reporting this to the maintainers of org.codehaus.groovy.vmplugin.v7.Java7$1
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release
| Grails Version: 4.0.2
| JVM Version: 13.0.2

$ gradle -version

Gradle 6.3

Build time: 2020-03-24 19:52:07 UTC
Revision: bacd40b727b0130eeac8855ae3f9fd9a0b207c60
Kotlin: 1.3.70
Groovy: 2.5.10
Ant: Apache Ant™ version 1.10.7 compiled on September 1 2019
JVM: 13.0.2 (Oracle Corporation 13.0.2+8)
OS: Linux 5.3.0-46-generic amd64

Um outro detalhe, como eu elimino esses WARNING chato de mais.

Ninguém?