Unable to access System property in Src code

I’d guess something like

task cucumber(type: JavaExec) {
   dependsOn assemble, compileTestJava
   systemProperty('env', System.properties['env'] ?: 'dev') 
   main = “io.cucumber.core.cli.Main”
   classpath = configurations.cucumberRuntime + sourceSets.main.output + sourceSets.test.output
   args = [’–plugin’, ‘pretty’, ‘–glue’, ‘CucumberTest’, ‘src/test/resources’]
}