Revised build for JDK 9 tolerance

We use AspectJ 1.9.0.BETA-1 for the ajc task now and exclude spring-oxm test compilation when running on JDK 9.

Issue: SPR-12549

build.gradle

@@ -116,6 +116,7 @@ configure(allprojects) { project ->
 
 	repositories {
 		maven { url "https://repo.spring.io/libs-release" }
+		maven { url "https://repo.spring.io/milestone" }
 	}
 
 	dependencies {
@@ -542,6 +543,11 @@ project("spring-oxm") {
 		targetCompatibility=1.6
 	}
 
+	if (System.getProperty("java.version").contains("1.9.")) {
+		// necessary because castor and xjc tasks cannot find the JDK's compiler on JDK 9
+		compileTestJava.enabled = false
+	}
+
 	dependencies {
 		compile(project(":spring-beans"))
 		compile(project(":spring-core"))
@@ -563,9 +569,11 @@ project("spring-oxm") {
 		testCompile("org.codehaus.jettison:jettison:1.3.7") {
 			exclude group: 'stax', module: 'stax-api'
 		}
-		testCompile(files(genCastor.classesDir).builtBy(genCastor))
-		testCompile(files(genJaxb.classesDir).builtBy(genJaxb))
-		testCompile(files(genXmlbeans.classesDir).builtBy(genXmlbeans))
+		if (compileTestJava.enabled) {
+			testCompile(files(genCastor.classesDir).builtBy(genCastor))
+			testCompile(files(genJaxb.classesDir).builtBy(genJaxb))
+			testCompile(files(genXmlbeans.classesDir).builtBy(genXmlbeans))
+		}
 	}
 }
 
@@ -1018,7 +1026,7 @@ project("spring-aspects") {
 
 	dependencies {
 		aspects(project(":spring-orm"))
-		ajc("org.aspectj:aspectjtools:${aspectjVersion}")
+		ajc("org.aspectj:aspectjtools:1.9.0.BETA-1")  // for the ability to build on JDK 9, not exposed in the POMs yet
 		rt("org.aspectj:aspectjrt:${aspectjVersion}")
 		compile("org.aspectj:aspectjweaver:${aspectjVersion}")
 		provided("org.eclipse.persistence:javax.persistence:2.0.0")