diff --git a/spring-core/src/main/java/org/springframework/core/convert/support/ByteBufferConverter.java b/spring-core/src/main/java/org/springframework/core/convert/support/ByteBufferConverter.java
index 75f19977024..43a94eeac7d 100644
--- a/spring-core/src/main/java/org/springframework/core/convert/support/ByteBufferConverter.java
+++ b/spring-core/src/main/java/org/springframework/core/convert/support/ByteBufferConverter.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 +16,7 @@
 
 package org.springframework.core.convert.support;
 
+import java.nio.Buffer;
 import java.nio.ByteBuffer;
 import java.util.Collections;
 import java.util.HashSet;
@@ -26,8 +27,8 @@ import org.springframework.core.convert.TypeDescriptor;
 import org.springframework.core.convert.converter.ConditionalGenericConverter;
 
 /**
- * Converts a {@link ByteBuffer} directly to and from {@code byte[]}s and indirectly to
- * any type that the {@link ConversionService} support via {@code byte[]}.
+ * Converts a {@link ByteBuffer} directly to and from {@code byte[]}s and indirectly
+ * to any type that the {@link ConversionService} support via {@code byte[]}.
  *
  * @author Phillip Webb
  * @since 4.0
@@ -47,7 +48,7 @@ final class ByteBufferConverter implements ConditionalGenericConverter {
 	}
 
 
-	private ConversionService conversionService;
+	private final ConversionService conversionService;
 
 
 	public ByteBufferConverter(ConversionService conversionService) {
@@ -72,18 +73,17 @@ final class ByteBufferConverter implements ConditionalGenericConverter {
 	}
 
 	private boolean matchesFromByteBuffer(TypeDescriptor targetType) {
-		return (targetType.isAssignableTo(BYTE_ARRAY_TYPE) || this.conversionService.canConvert(
-				BYTE_ARRAY_TYPE, targetType));
+		return (targetType.isAssignableTo(BYTE_ARRAY_TYPE) ||
+				this.conversionService.canConvert(BYTE_ARRAY_TYPE, targetType));
 	}
 
 	private boolean matchesToByteBuffer(TypeDescriptor sourceType) {
-		return (sourceType.isAssignableTo(BYTE_ARRAY_TYPE) || this.conversionService.canConvert(
-				sourceType, BYTE_ARRAY_TYPE));
+		return (sourceType.isAssignableTo(BYTE_ARRAY_TYPE) ||
+				this.conversionService.canConvert(sourceType, BYTE_ARRAY_TYPE));
 	}
 
 	@Override
-	public Object convert(Object source, TypeDescriptor sourceType,
-			TypeDescriptor targetType) {
+	public Object convert(Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {
 		if (sourceType.isAssignableTo(BYTE_BUFFER_TYPE)) {
 			return convertFromByteBuffer((ByteBuffer) source, targetType);
 		}
@@ -104,11 +104,17 @@ final class ByteBufferConverter implements ConditionalGenericConverter {
 	}
 
 	private Object convertToByteBuffer(Object source, TypeDescriptor sourceType) {
-		byte[] bytes = (byte[]) (source instanceof byte[] ? source
-				: this.conversionService.convert(source, sourceType, BYTE_ARRAY_TYPE));
+		byte[] bytes = (byte[]) (source instanceof byte[] ? source :
+				this.conversionService.convert(source, sourceType, BYTE_ARRAY_TYPE));
+
 		ByteBuffer byteBuffer = ByteBuffer.allocate(bytes.length);
 		byteBuffer.put(bytes);
-		byteBuffer.rewind();
+
+		// Extra cast necessary for compiling on JDK 9 plus running on JDK 8, since
+		// otherwise the overridden ByteBuffer-returning rewind method would be chosen
+		// which isn't available on JDK 8.
+		((Buffer) byteBuffer).rewind();
+
 		return byteBuffer;
 	}
 
diff --git a/spring-core/src/test/java/org/springframework/core/io/support/PathMatchingResourcePatternResolverTests.java b/spring-core/src/test/java/org/springframework/core/io/support/PathMatchingResourcePatternResolverTests.java
index 6c1128ef21e..5c1f0833f77 100644
--- a/spring-core/src/test/java/org/springframework/core/io/support/PathMatchingResourcePatternResolverTests.java
+++ b/spring-core/src/test/java/org/springframework/core/io/support/PathMatchingResourcePatternResolverTests.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.
@@ -25,6 +25,7 @@ import java.util.List;
 import org.junit.Ignore;
 import org.junit.Test;
 
+import org.springframework.core.JdkVersion;
 import org.springframework.core.io.Resource;
 
 import static org.junit.Assert.*;
@@ -82,7 +83,8 @@ public class PathMatchingResourcePatternResolverTests {
 	public void testSingleResourceInJar() throws IOException {
 		Resource[] resources = resolver.getResources("java/net/URL.class");
 		assertEquals(1, resources.length);
-		assertProtocolAndFilename(resources[0], "jar", "URL.class");
+		String expectedProtocol = (JdkVersion.getMajorJavaVersion() < JdkVersion.JAVA_19 ? "jar" : "jrt");
+		assertProtocolAndFilename(resources[0], expectedProtocol, "URL.class");
 	}
 
 	@Ignore // passes under eclipse, fails under ant
diff --git a/spring-core/src/test/java/org/springframework/tests/JavaVersion.java b/spring-core/src/test/java/org/springframework/tests/JavaVersion.java
index b36319b2c4e..ac4e78adeab 100644
--- a/spring-core/src/test/java/org/springframework/tests/JavaVersion.java
+++ b/spring-core/src/test/java/org/springframework/tests/JavaVersion.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.
@@ -24,12 +24,6 @@ package org.springframework.tests;
  */
 public enum JavaVersion {
 
-
-	/**
-	 * Java 1.5
-	 */
-	JAVA_15("1.5", 15),
-
 	/**
 	 * Java 1.6
 	 */
@@ -43,7 +37,12 @@ public enum JavaVersion {
 	/**
 	 * Java 1.8
 	 */
-	JAVA_18("1.8", 18);
+	JAVA_18("1.8", 18),
+
+	/**
+	 * Java 1.9
+	 */
+	JAVA_19("1.9", 19);
 
 
 	private static final JavaVersion runningVersion = findRunningVersion();
@@ -55,7 +54,7 @@ public enum JavaVersion {
 				return candidate;
 			}
 		}
-		return JavaVersion.JAVA_15;
+		return JavaVersion.JAVA_16;
 	}
 
 
@@ -81,16 +80,16 @@ public enum JavaVersion {
 	 * @return {@code true} if the specified version is at least this version
 	 */
 	public boolean isAtLeast(JavaVersion version) {
-		return this.value >= version.value;
+		return (this.value >= version.value);
 	}
 
-
 	/**
 	 * Returns the current running JDK version. If the current version cannot be
-	 * determined {@link #JAVA_15} will be returned.
+	 * determined {@link #JAVA_16} will be returned.
 	 * @return the JDK version
 	 */
 	public static JavaVersion runningVersion() {
 		return runningVersion;
 	}
+
 }
diff --git a/spring-core/src/test/java/org/springframework/tests/JavaVersionTests.java b/spring-core/src/test/java/org/springframework/tests/JavaVersionTests.java
index 4ca944d9b42..05c341fb94d 100644
--- a/spring-core/src/test/java/org/springframework/tests/JavaVersionTests.java
+++ b/spring-core/src/test/java/org/springframework/tests/JavaVersionTests.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.
@@ -36,8 +36,8 @@ public class JavaVersionTests {
 
 	@Test
 	public void isAtLeast() throws Exception {
-		assertTrue(JavaVersion.JAVA_16.isAtLeast(JavaVersion.JAVA_15));
 		assertTrue(JavaVersion.JAVA_16.isAtLeast(JavaVersion.JAVA_16));
 		assertFalse(JavaVersion.JAVA_16.isAtLeast(JavaVersion.JAVA_17));
 	}
+
 }