How do I add default JVM arguments with Gradle

问题:

I need to add default JVM options to my jar, when build with Gradle. From the documentation I got that I have to set:

applicationDefaultJvmArgs = ["-Djavafx.embed.singleThread=true"]

I have not much experience with Gradle and the developer that wrote the build.gradle file wrote it different from what most websites give as examples.

Here is the build.gradle:

apply plugin: 'java'
apply plugin: 'eclipse'

version = '0.1'

repositories {
    mavenCentral()
}

dependencies {
    testCompile group: 'junit', name: 'junit', version: '4.+'
    compile 'placeholder'
}

task release(type: Jar) {
    manifest {
        attributes("Implementation-Title": "placeholder",
                "Implementation-Version": version,
                'Main-Class': 'placeholder.Application')
    }
    from { configurations.compile.collect { it.isDirectory() ? it : zipTree(it) } }

    with jar
}

task wrapper(type: Wrapper) {
    gradleVersion = '2.2.1'
}

I don't know where to put the arguments. I tried putting them in different locations, but I always get:

A problem occurred evaluating root project 'placeholder'.
> No such property: applicationDefaultJvmArgs for class: org.gradle.api.tasks.bundling.Jar_Decorated

Much Thanks, Jhonny

回答1:

From the top of my head I can think of 2 options:

Option1: Do what @Ethan said, it'll likely work:

package placeholder;

//your imports

public class Application{
  static {
      System.getProperties().set("javafx.embed.singleThread", "true");  
  }
  // your code
  public static void main(String... args){
    //your code
  }
}

Option 2: Use the application plugin + default jvm values

build.gradle:

apply plugin: 'application'
//your code
applicationDefaultJvmArgs = ["-Djavafx.embed.singleThread=true"]

Now you can run your code 2 ways:

From gradle

$gradle run

From distribution(script). from the generated script that the application plugin will provide:

$gradle clean build distZip

Then gradle will generate a zip file somewhere under ${your.projectdir}/build. Find the zip then unzip it and under /bin you'll find a ${yourproject}.bat and ${yourproject} executables. One is for Linux/mac/unix (${yourproject}) the other one is for windows (${yourproject.bat})

回答2:

applicationDefaultJvmArgs is provided by the Application plugin. So if you apply that plugin, the error would probably go away, and you should be able to execute the program by issuing gradle run once you set the mainClassName property to the fully qualified class name, the main method of which you want to invoke.

回答3:

you can use command-line with gradle task：

class AppRun extends JavaExec {
    private boolean withDebug

    @Option(option = "with-debug", description = "enable debug for the process. ")
    public void setDebugMode(boolean debug) {
        this.withDebug = debug
    }

    public boolean getDebugMode() {
        return this.withDebug
    }
}

task run(type: AppRun) {
}

then run task with options

gradle run --with-debug