How to execute a task of type 'JavaExec' before compileJava

Question

I need to execute a java class which has a main method in it before compiling the code. This is what I have tried so far:

task runSimple(type: JavaExec) {
    main = 'jjrom.ObjectGen'
    classpath = sourceSets.main.runtimeClasspath
    File prop1 = file(propFilePath)
    args '-sqlserver', '-force', prop1.path
    println "I'm done executing."
}
compileJava {
    dependsOn runSimple
}

When I execute this script with the command "gradle compileJava" , I get this error message:

I'm done executing.

FAILURE: Build failed with an exception.

What went wrong: Circular dependency between the following task: :classes --- :compileJava --- :runSimple --- :classes (*)

Answer 1

If you need to execute this class before compiling the code, you can't give it classpath = sourceSets.main.runtimeClasspath. The latter includes the compiled code, and so Gradle automatically infers runSimple.dependsOn compileJava, which together with your compileJava.dependsOn runSimple gives a cyclic task dependency. (To be precise, Gradle infers runSimple.dependsOn classes, which in turn depends on compileJava.)

Answer 2

If you need to run JavaExec only with dependecies classpath, just change classpath variable to something like:

classpath = configurations.compile

Or if you are interested in very specific classpath, you could add custom configuration like this:

configurations {
    customClasspath
}

dependencies {
    customClasspath files('path/to/your.jar')
}

task runSimple(type: JavaExec) {
    main = 'jjrom.ObjectGen'
    classpath = configurations.customClasspath
    File prop1 = file(propFilePath)
    args '-sqlserver', '-force', prop1.path
    println "I'm done executing."
}

compileJava {
    dependsOn runSimple
}