android launch issues. Unsupported class file major version 57

Question

I have followed the mac android getting started but when I run-android it fails with the following error(s). I\'ve tried to find the answer online but I cant seem to find a

Answer 1

I landed on this page after searching for this error when I did ./gradlew bootRun as described in the Okta Spring Security Authentication Example. Indeed I have OpenJDK13 on Ubuntu 20:

$ java --version
openjdk 13.0.3 2020-04-14
OpenJDK Runtime Environment (build 13.0.3+3-Ubuntu-1ubuntu2)
OpenJDK 64-Bit Server VM (build 13.0.3+3-Ubuntu-1ubuntu2, mixed mode)

I didn't like the idea of downgrading my Java version, so instead I upgraded Gradle and rebuilt gradlew which is a wrapper that is specific to the project. Before attempting this solution, make sure that you're using version control or have a backup of the current project.

These were the steps:

1) Install skdkman to easily install gradle. Using apt install gave me an ancient version.

curl -s "https://get.sdkman.io" | bash
source "$HOME/.sdkman/bin/sdkman-init.sh"

2) Check that sdkman installed correctly

sdk version

3) Install gradle 6

sdk install gradle 6.5

4) Rebuild gradlew on the same directory

gradle wrapper

5) Run application

./gradlew bootRun

You should see something like this:

Downloading https://services.gradle.org/distributions/gradle-6.5-bin.zip
.........10%..........20%..........30%..........40%.........50%..........60%..........70%..........80%.........90%..........100%

> Task :bootRun

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v2.1.5.RELEASE)

Doing git status shows that many files have changed:

Changes not staged for commit:
  (use "git add ..." to update what will be committed)
  (use "git restore ..." to discard changes in working directory)
    modified:   gradle/wrapper/gradle-wrapper.jar
    modified:   gradle/wrapper/gradle-wrapper.properties
    modified:   gradlew
    modified:   gradlew.bat

For my usage, I'll simply commit these changes in my own branch.