How to run JavaExec with out compile - gradle

Question

I run a gradle javaexec in build.gradle
task main(type: JavaExec) {
main = 'com.gtan.Application'
classpath = sourceSets.main.runtimeClasspath
}
this is the output result:
:compileJava UP-TO-DATE
:compileScala UP-TO-DATE
:processResources UP-TO-DATE
:classes UP-TO-DATE
:main
i want run this javaexec without compile tasks. like:
:main
what should i do ?

Answer 1

When you set up the classpath as the runtime classpath from the main sourceSet, you're telling Gradle that your task depends on the output from the main sourceSet. So, it will compile the main source set first, in order to ensure that the classpath is correctly set up for your JavaExec task.
The answer to your question depends on where the com.gtan.Application class is, and what classpath the application is expecting. If this class resides in the local project, under src/main/java, you won't be able to get rid of compilation, because Gradle must compile this class in order to execute it.
If the class lives in a JAR that your build depends on, for example:
dependencies {
runtime 'com.gtan:this-example-has-what-to-run:1.0.0'
}
Then, you can change your task definition to:
task main(type: JavaExec) {
main = 'com.gtan.Application'
classpath = configurations.runtime
}
By setting the classpath to a configuration, Gradle does not need to perform any compilation, and you get:
$ ./gradlew main
:main