gradle java9 Could not target platform: 'Java SE 9' using tool chain: 'JDK 8 (1.8)'

Question

I want to use java9 on my gradle project inside eclipse oxygen. When I run:

Run as> Gradle Test on  GreeterTest.java

with the followin

Answer 1

I had a similar issue with eclipse, I had to set JAVA_HOME in Properties -> Gradle.

Answer 2

You should probably try to update your JAVA_HOME in system variables and Java version used in eclipse to be consistent to

JAVA_HOME=/path/to/jdk9

In MacOSX, something like :

JAVA_HOME = /Library/Java/JavaVirtualMachines/jdk-9.0.1.jdk/Contents/Home/bin

As informed in comments, the default path on Linux would be :

/usr/lib/jvm/java-9-openjdk

Answer 3

For me the problem was that I used

compileOptions {
    sourceCompatibility JavaVersion.VERSION_1_10
    targetCompatibility JavaVersion.VERSION_1_10
}

but the project was configured for Java 1.8. So I changed these to 1_8 and it works.

Answer 4

I faced the issue because in IntelliJ Idea in the Settings > Build Tools > Gradle In "Gradle" section, Gradlje JVM used an incorrect Java version. So I specify to use JAVA_HOME and it fixes the issue.

Answer 5

From what I can see, it is the Gradle version issue. (Gradle and Java 9 compatibility issue).

You need to upgrade the wrapper to 4.3.1, cli ref:

# upgrade Gradle to 4.3.1 
gradle wrapper --gradle-version 4.3.1 # not ./gradlew

Let me know if that works.

Answer 6

What I did to fix this problem was I did this on my imported project build.gradle on compileJava section I changed sourceCompatibility and targetCompatibility into 8. It works for me. this happen when you import project from other resource, which is build in different version.