Deprecate JdkVersion (for optimistic compatibility with newer JDK generations)

Issue: SPR-13312

spring-core/src/main/java/org/springframework/core/DefaultParameterNameDiscoverer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2013 the original author or authors.
+ * Copyright 2002-2015 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,6 +16,8 @@
 
 package org.springframework.core;
 
+import org.springframework.util.ClassUtils;
+
 /**
  * Default implementation of the {@link ParameterNameDiscoverer} strategy interface,
  * using the Java 8 standard reflection mechanism (if available), and falling back
@@ -31,8 +33,8 @@ package org.springframework.core;
  */
 public class DefaultParameterNameDiscoverer extends PrioritizedParameterNameDiscoverer {
 
-	private static final boolean standardReflectionAvailable =
-			(JdkVersion.getMajorJavaVersion() >= JdkVersion.JAVA_18);
+	private static final boolean standardReflectionAvailable = ClassUtils.isPresent(
+			"java.lang.reflect.Executable", DefaultParameterNameDiscoverer.class.getClassLoader());
 
 
 	public DefaultParameterNameDiscoverer() {

spring-core/src/main/java/org/springframework/core/JdkVersion.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2013 the original author or authors.
+ * Copyright 2002-2015 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -27,7 +27,10 @@ package org.springframework.core;
  * @author Juergen Hoeller
  * @author Rick Evans
  * @author Sam Brannen
+ * @deprecated as of Spring 4.2.1, in favor of direct checks for the desired
+ * JDK API variants via reflection
  */
+@Deprecated
 public abstract class JdkVersion {
 
 	/**

spring-jdbc/src/main/java/org/springframework/jdbc/core/SqlRowSetResultSetExtractor.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2015 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -22,7 +22,6 @@ import javax.sql.rowset.CachedRowSet;
 import javax.sql.rowset.RowSetFactory;
 import javax.sql.rowset.RowSetProvider;
 
-import org.springframework.core.JdkVersion;
 import org.springframework.jdbc.support.rowset.ResultSetWrappingSqlRowSet;
 import org.springframework.jdbc.support.rowset.SqlRowSet;
 import org.springframework.lang.UsesJava7;
@@ -34,8 +33,8 @@ import org.springframework.util.ClassUtils;
  *
  * <p>The default implementation uses a standard JDBC CachedRowSet underneath.
  * This means that JDBC RowSet support needs to be available at runtime:
- * by default, Sun's {@code com.sun.rowset.CachedRowSetImpl} class on Java 5 and 6,
- * or the {@code javax.sql.rowset.RowSetProvider} mechanism on Java 7 / JDBC 4.1.
+ * by default, Sun's {@code com.sun.rowset.CachedRowSetImpl} class on Java 6,
+ * or the {@code javax.sql.rowset.RowSetProvider} mechanism on Java 7+ / JDBC 4.1+.
  *
  * @author Juergen Hoeller
  * @since 1.2
@@ -49,12 +48,13 @@ public class SqlRowSetResultSetExtractor implements ResultSetExtractor<SqlRowSet
 	private static final CachedRowSetFactory cachedRowSetFactory;
 
 	static {
-		if (JdkVersion.getMajorJavaVersion() >= JdkVersion.JAVA_17) {
-			// using JDBC 4.1 RowSetProvider
+		if (ClassUtils.isPresent("javax.sql.rowset.RowSetProvider",
+				SqlRowSetResultSetExtractor.class.getClassLoader())) {
+			// using JDBC 4.1 RowSetProvider, available on JDK 7+
 			cachedRowSetFactory = new StandardCachedRowSetFactory();
 		}
 		else {
-			// JDBC 4.1 API not available - fall back to Sun CachedRowSetImpl
+			// JDBC 4.1 API not available - fall back to Sun CachedRowSetImpl on JDK 6
 			cachedRowSetFactory = new SunCachedRowSetFactory();
 		}
 	}

spring-oxm/src/main/java/org/springframework/oxm/jaxb/Jaxb2Marshaller.java

@@ -80,7 +80,6 @@ import org.xml.sax.helpers.XMLReaderFactory;
 
 import org.springframework.beans.factory.BeanClassLoaderAware;
 import org.springframework.beans.factory.InitializingBean;
-import org.springframework.core.JdkVersion;
 import org.springframework.core.annotation.AnnotationUtils;
 import org.springframework.core.io.Resource;
 import org.springframework.oxm.GenericMarshaller;
@@ -577,27 +576,28 @@ public class Jaxb2Marshaller implements MimeMarshaller, MimeUnmarshaller, Generi
 	}
 
 	@Override
+	@SuppressWarnings("deprecation")
 	public boolean supports(Type genericType) {
 		if (genericType instanceof ParameterizedType) {
 			ParameterizedType parameterizedType = (ParameterizedType) genericType;
 			if (JAXBElement.class == parameterizedType.getRawType() &&
 					parameterizedType.getActualTypeArguments().length == 1) {
+				boolean isJdk6 = (org.springframework.core.JdkVersion.getMajorJavaVersion() <= org.springframework.core.JdkVersion.JAVA_16);
 				Type typeArgument = parameterizedType.getActualTypeArguments()[0];
 				if (typeArgument instanceof Class) {
 					Class<?> classArgument = (Class<?>) typeArgument;
-					if (JdkVersion.getMajorJavaVersion() >= JdkVersion.JAVA_17 && classArgument.isArray()) {
-						return classArgument.getComponentType().equals(Byte.TYPE);
-					}
-					else {
+					if (isJdk6 && classArgument.isArray()) {
 						return (isPrimitiveWrapper(classArgument) || isStandardClass(classArgument) ||
 								supportsInternal(classArgument, false));
 					}
+					else {
+						return (classArgument.getComponentType() == Byte.TYPE);
+					}
 				}
-				else if (JdkVersion.getMajorJavaVersion() <= JdkVersion.JAVA_16 &&
-						typeArgument instanceof GenericArrayType) {
+				else if (isJdk6 && typeArgument instanceof GenericArrayType) {
 					// see http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=5041784
 					GenericArrayType arrayType = (GenericArrayType) typeArgument;
-					return arrayType.getGenericComponentType().equals(Byte.TYPE);
+					return (arrayType.getGenericComponentType() == Byte.TYPE);
 				}
 			}
 		}