modify gradle compiler args

A simple java-agent makes your Gradle journey much more fluent!

1. replace --release to -source and -target when using gradle.
2. flush for every PipedOutputStream write.

How to use?

1. compile

./gradlew clean shadowJar

2. copy to gradle folder

Copy agent/build/libs/modify-gradle-compiler-args-agent.jar to ~/.gradle/

3. modify gradle.properties

org.gradle.jvmargs=--add-opens java.base/jdk.internal.org.objectweb.asm=ALL-UNNAMED --add-opens java.base/jdk.internal.org.objectweb.asm.tree=ALL-UNNAMED -javaagent:../../modify-gradle-compiler-args-agent.jar

4. stop old daemon

./gradlew --stop

5. enjoy!

./gradlew compileJava

Use case

1. replace --release

When java.toolchain.languageVersion is set to a non-null value in build.gradle, the argument --source will be added to the compiler arguments.
If you need to use some jdk internal classes like --add-exports=java.base/jdk.internal.misc=xxx, the compiler will tell you that you cannot export the packages when using --release.

This java-agent removes --release argument and place the value into -source and -target arguments, so that you can finish your build.

2. flush PipedOutputStream

Gradle uses PipedOutputStream for forwarding stdin to application in JavaExec tasks.
However PipedOutputStream doesn't auto-flush the stream and you can only get data after 1 second.
This java-agent automatically flushes the PipedOutputStream for every write, so that you can use JavaExec with stdin smoothly.