Drop outdated support for building on JDK 9 (not compatible with JDK 9 b111+)

build.gradle

@@ -130,8 +130,6 @@ configure(allprojects) { project ->
 
 	repositories {
 		maven { url "https://repo.spring.io/libs-release" }
-		maven { url "https://repo.spring.io/milestone" }
-		maven { url "https://repo.spring.io/snapshot" }   // reactor 2.0.6 snapshot
 	}
 
 	dependencies {
@@ -566,11 +564,6 @@ project("spring-oxm") {
 		targetCompatibility = 1.6
 	}
 
-	if (!System.getProperty("java.version").contains("1.8.")) {
-		// 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"))