Enforce the usage of OpenJDK as Java VM. Advance version to 1.1.0

REAME.md

@@ -0,0 +1,8 @@
+# MAVEN PARENT POM
+
+A parent pom for all the gCube artifacts.
+
+# Enforcements 
+* Java 8 (target and source)
+* OpenJDK as target Java VM.
+* Maven 3.0.0+

pom.xml

@@ -5,7 +5,7 @@
 
 	<groupId>org.gcube.tools</groupId>
 	<artifactId>maven-parent</artifactId>
-	<version>1.0.0</version>
+	<version>1.1.0</version>
 	<packaging>pom</packaging>
 
 	<!-- gCube repositories -->
@@ -335,6 +335,12 @@
 								<!--requireJavaVersion>
 									<version>${java_version}</version>
 								</requireJavaVersion-->
+								<requireProperty>
+									<property>java.vm.name</property>
+									<message>Java Vendor must be OpenJDK.</message>
+									<regex>${java.expected.vm}</regex>
+									<regexMessage>Java Vendor must be OpenJDK. Found: ${java.vm.name}</regexMessage>
+								</requireProperty>
 							</rules>
 						</configuration>
 					</execution>
@@ -382,6 +388,7 @@
 		<distroDirectory>distro</distroDirectory>
 
 		<java_version>1.8</java_version>
+		<java.expected.vm>.*OpenJDK.*</java.expected.vm>
 		<maven.compiler.source>${java_version}</maven.compiler.source>
 		<maven.compiler.target>${java_version}</maven.compiler.target>