Make source code compatible with JDK 8

Closes gh-10695

Author: marcusdacoregio

build.gradle

@@ -106,6 +106,8 @@ subprojects {
 	}
 	tasks.withType(JavaCompile) {
 		options.encoding = "UTF-8"
+		options.compilerArgs.add("-parameters")
+		options.release = 8
 	}
 }
 

config/src/main/java/org/springframework/security/config/annotation/web/configurers/saml2/Saml2LoginConfigurer.java

@@ -276,8 +276,7 @@ private String version() {
 		if (version != null) {
 			return version;
 		}
-		return Version.class.getModule().getDescriptor().version().map(Object::toString)
-				.orElseThrow(() -> new IllegalStateException("cannot determine OpenSAML version"));
+		return Version.getVersion();
 	}
 
 	private void registerDefaultAuthenticationProvider(B http) {

config/src/test/java/org/springframework/security/config/annotation/web/configurers/NamespaceHttpX509Tests.java

@@ -21,11 +21,13 @@
 import java.security.cert.CertificateFactory;
 import java.security.cert.X509Certificate;
 
+import javax.security.auth.x500.X500Principal;
 import javax.servlet.http.HttpServletRequest;
 
+import org.bouncycastle.asn1.x500.X500Name;
+import org.bouncycastle.asn1.x500.style.BCStyle;
 import org.junit.Rule;
 import org.junit.Test;
-import sun.security.x509.X500Name;
 
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.context.annotation.Bean;
@@ -239,12 +241,8 @@ protected void configure(HttpSecurity http) throws Exception {
 		}
 
 		private String extractCommonName(X509Certificate certificate) {
-			try {
-				return ((X500Name) certificate.getSubjectDN()).getCommonName();
-			}
-			catch (Exception ex) {
-				throw new IllegalArgumentException(ex);
-			}
+			X500Principal principal = certificate.getSubjectX500Principal();
+			return new X500Name(principal.getName()).getRDNs(BCStyle.CN)[0].getFirst().getValue().toString();
 		}
 
 	}