Use main/mainClass depending on Gradle version

core-plugin/src/main/groovy/com/github/jrubygradle/api/gems/GemUtils.groovy

@@ -23,6 +23,7 @@
  */
 package com.github.jrubygradle.api.gems
 
+import groovy.transform.CompileDynamic
 import groovy.transform.CompileStatic
 import groovy.util.logging.Slf4j
 import org.gradle.api.Action
@@ -33,6 +34,7 @@ import org.gradle.api.file.CopySpec
 import org.gradle.api.file.DuplicateFileCopyingException
 import org.gradle.api.file.FileCollection
 import org.gradle.process.JavaExecSpec
+import org.ysb33r.grolifant.api.core.LegacyLevel
 import org.ysb33r.grolifant.api.core.OperatingSystem
 import org.ysb33r.grolifant.api.core.ProjectOperations
 
@@ -178,6 +180,7 @@ class GemUtils {
             log.info("Installing ${gemsToProcess*.name.join(',')}")
 
             project.javaexec { JavaExecSpec spec ->
+                setMainClass(spec, JRUBY_MAINCLASS)
                 spec.with {
                     // Setting these environment variables will ensure that
                     // jbundler and/or jar-dependencies will not attempt to invoke
@@ -187,7 +190,6 @@ class GemUtils {
                         JARS_SKIP: true,
                         GEM_HOME: destDir.absolutePath,
                         GEM_PATH: destDir.absolutePath
-                    mainClass = JRUBY_MAINCLASS
                     classpath jRubyClasspath
                     args '-S', GEM, 'install'
 
@@ -467,6 +469,15 @@ class GemUtils {
         }
     }
 
+    @CompileDynamic
+    private void setMainClass(JavaExecSpec spec, String mainClassName) {
+        if(LegacyLevel.PRE_7_0) {
+            spec.main = mainClassName
+        } else {
+            spec.mainClass = mainClassName
+        }
+    }
+
     private static final String GEM = 'gem'
     private static final String GEM_EXTENSION = '.gem'
     private static final String EVERYTHING = '**'

gradle.properties

@@ -14,7 +14,7 @@ releaseBuild=false
 targetCompatibility=1.8
 sourceCompatibility=1.8
 
-grolifantVersion=1.0.0-alpha.6
+grolifantVersion=1.3.3
 jrubyVersion=9.2.9.0
 jettyVersion=9.2.12.v20150709
 bcprovVersion=1.46