Improve Gradle build.

Author: SoftlySplinter

build.gradle

@@ -12,8 +12,6 @@ plugins
 group = 'com.ibm.cicsdev.springboot'
 archivesBaseName='cics-java-liberty-springboot-transactions'
 version = '0.1.0'
-sourceCompatibility = '1.8'
-
 
 // If in Eclipse, add Javadoc to the local project classpath
 eclipse
@@ -30,6 +28,15 @@ repositories
 	mavenCentral()
 }
 
+java
+{
+    toolchain
+    {
+        languageVersion = JavaLanguageVersion.of(java_version)
+        vendor = JvmVendorSpec.IBM
+        implementation = JvmImplementation.J9
+    }
+}
 
 dependencies
 {    

gradle.properties

@@ -13,4 +13,5 @@
 # These values only have any effect if the publish goal is used.
 # For example: gradle build publish.
 publish_repo_releases_url = 'default-value-for-publish_repo_releases_url'
-publish_repo_releases_name = 'default-value-for-publish_repo_releases_name'
+publish_repo_releases_name = 'default-value-for-publish_repo_releases_name'
+java_version = 8