GenericTypeResolver's resolveTypeArguments needs to return null for raw types (for backwards compatibility with 3.2)

Issue: SPR-11052

Author: jhoeller

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

@@ -240,12 +240,12 @@ private static Class<?> getSingleGeneric(ResolvableType resolvableType) {
 	 * @return the resolved type of each argument, with the array size matching the
 	 * number of actual type arguments, or {@code null} if not resolvable
 	 */
-	public static Class[] resolveTypeArguments(Class<?> clazz, Class<?> genericIfc) {
+	public static Class<?>[] resolveTypeArguments(Class<?> clazz, Class<?> genericIfc) {
 		ResolvableType type = ResolvableType.forClass(clazz).as(genericIfc);
-		if (!type.hasGenerics()) {
+		if (!type.hasGenerics() || type.hasUnresolvableGenerics()) {
 			return null;
 		}
-		return type.resolveGenerics(Object.class);
+		return type.resolveGenerics();
 	}
 
 	/**

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

@@ -567,7 +567,7 @@ public Class<?> resolve(Class<?> fallback) {
 			this.resolved = resolveClass();
 			this.isResolved = true;
 		}
-		return (this.resolved == null ? fallback : this.resolved);
+		return (this.resolved != null ? this.resolved : fallback);
 	}
 
 	private Class<?> resolveClass() {
@@ -576,7 +576,7 @@ private Class<?> resolveClass() {
 		}
 		if (this.type instanceof GenericArrayType) {
 			Class<?> resolvedComponent = getComponentType().resolve();
-			return (resolvedComponent == null ? null : Array.newInstance(resolvedComponent, 0).getClass());
+			return (resolvedComponent != null ? Array.newInstance(resolvedComponent, 0).getClass() : null);
 		}
 		return resolveType().resolve();
 	}

spring-core/src/test/java/org/springframework/core/GenericTypeResolverTests.java

@@ -138,10 +138,17 @@ public void testGetTypeVariableMap() throws Exception {
 	}
 
 	@Test
-	public void getGenericsCannotBeResovled() throws Exception {
+	public void getGenericsCannotBeResolved() throws Exception {
 		// SPR-11030
-		Class[] resolved = GenericTypeResolver.resolveTypeArguments(List.class, Iterable.class);
-		assertThat(resolved, equalTo(new Class[] { Object.class }));
+		Class<?>[] resolved = GenericTypeResolver.resolveTypeArguments(List.class, Iterable.class);
+		assertNull(resolved);
+	}
+
+	@Test
+	public void getRawMapTypeCannotBeResolved() throws Exception {
+		// SPR-11052
+		Class<?>[] resolved = GenericTypeResolver.resolveTypeArguments(Map.class, Map.class);
+		assertNull(resolved);
 	}
 
 	@Test
@@ -300,11 +307,9 @@ class TypedNested extends Nested<Long> {
 	static abstract class WithArrayBase<T> {
 
 		public abstract T[] array(T... args);
-
 	}
 
 	static abstract class WithArray<T> extends WithArrayBase<T> {
-
 	}
 
 }

spring-websocket/src/main/java/org/springframework/web/socket/adapter/ConvertingEncoderDecoderSupport.java

@@ -17,7 +17,6 @@
 package org.springframework.web.socket.adapter;
 
 import java.nio.ByteBuffer;
-
 import javax.websocket.DecodeException;
 import javax.websocket.Decoder;
 import javax.websocket.EncodeException;
@@ -65,10 +64,8 @@
  *
  * @author Phillip Webb
  * @since 4.0
- *
- * @param <T> The type being converted to (for Encoder) or from (for Decoder)
- * @param <M> The WebSocket message type ({@link String} or {@link ByteBuffer})
- *
+ * @param <T> the type being converted to (for Encoder) or from (for Decoder)
+ * @param <M> the WebSocket message type ({@link String} or {@link ByteBuffer})
  * @see ConvertingEncoderDecoderSupport.BinaryEncoder
  * @see ConvertingEncoderDecoderSupport.BinaryDecoder
  * @see ConvertingEncoderDecoderSupport.TextEncoder
@@ -107,15 +104,13 @@ public void destroy() {
 	 */
 	protected ConversionService getConversionService() {
 		ApplicationContext applicationContext = getApplicationContext();
-		Assert.state(applicationContext != null,
-				"Unable to locate the Spring ApplicationContext");
+		Assert.state(applicationContext != null, "Unable to locate the Spring ApplicationContext");
 		try {
 			return applicationContext.getBean(CONVERSION_SERVICE_BEAN_NAME, ConversionService.class);
 		}
 		catch (BeansException ex) {
-			throw new IllegalStateException(
-					"Unable to find ConversionService, please configure a '"
-							+ CONVERSION_SERVICE_BEAN_NAME + "' or override getConversionService()", ex);
+			throw new IllegalStateException("Unable to find ConversionService: please configure a '" +
+					CONVERSION_SERVICE_BEAN_NAME + "' or override the getConversionService() method", ex);
 		}
 	}
 
@@ -148,8 +143,12 @@ protected TypeDescriptor getMessageType() {
 	}
 
 	private Class<?>[] resolveTypeArguments() {
-		return GenericTypeResolver.resolveTypeArguments(getClass(),
-				ConvertingEncoderDecoderSupport.class);
+		Class<?>[] resolved = GenericTypeResolver.resolveTypeArguments(getClass(), ConvertingEncoderDecoderSupport.class);
+		if (resolved == null) {
+			throw new IllegalStateException("ConvertingEncoderDecoderSupport's generic types T and M " +
+					"need to be substituted in subclass: " + getClass());
+		}
+		return resolved;
 	}
 
 	/**
@@ -185,63 +184,56 @@ public T decode(M message) throws DecodeException {
 		}
 		catch (ConversionException ex) {
 			if (message instanceof String) {
-				throw new DecodeException((String) message, "Unable to decode " +
-						"websocket message using ConversionService", ex);
+				throw new DecodeException((String) message,
+						"Unable to decode websocket message using ConversionService", ex);
 			}
 			if (message instanceof ByteBuffer) {
-				throw new DecodeException((ByteBuffer) message, "Unable to decode " +
-						"websocket message using ConversionService", ex);
+				throw new DecodeException((ByteBuffer) message,
+						"Unable to decode websocket message using ConversionService", ex);
 			}
 			throw ex;
 		}
 	}
 
 
 	/**
-	 * A Binary {@link javax.websocket.Encoder.Binary javax.websocket.Encoder} that
-	 * delegates to Spring's conversion service. See
-	 * {@link ConvertingEncoderDecoderSupport} for details.
-	 *
-	 * @param <T> The type that this Encoder can convert to.
+	 * A binary {@link javax.websocket.Encoder.Binary javax.websocket.Encoder} that delegates
+	 * to Spring's conversion service. See {@link ConvertingEncoderDecoderSupport} for details.
+	 * @param <T> the type that this Encoder can convert to
 	 */
-	public static abstract class BinaryEncoder<T> extends
-			ConvertingEncoderDecoderSupport<T, ByteBuffer> implements Encoder.Binary<T> {
+	public static abstract class BinaryEncoder<T> extends ConvertingEncoderDecoderSupport<T, ByteBuffer>
+			implements Encoder.Binary<T> {
 	}
 
 
 	/**
-	 * A Binary {@link javax.websocket.Encoder.Binary javax.websocket.Encoder} that delegates
-	 * to Spring's conversion service. See {@link ConvertingEncoderDecoderSupport} for
-	 * details.
-	 *
-	 * @param <T> The type that this Decoder can convert from.
+	 * A binary {@link javax.websocket.Encoder.Binary javax.websocket.Encoder} that delegates
+	 * to Spring's conversion service. See {@link ConvertingEncoderDecoderSupport} for details.
+	 * @param <T> the type that this Decoder can convert from
 	 */
-	public static abstract class BinaryDecoder<T> extends
-			ConvertingEncoderDecoderSupport<T, ByteBuffer> implements Decoder.Binary<T> {
+	public static abstract class BinaryDecoder<T> extends ConvertingEncoderDecoderSupport<T, ByteBuffer>
+			implements Decoder.Binary<T> {
 	}
 
 
 	/**
-	 * A Text {@link javax.websocket.Encoder.Text javax.websocket.Encoder} that delegates
+	 * A text {@link javax.websocket.Encoder.Text javax.websocket.Encoder} that delegates
 	 * to Spring's conversion service. See {@link ConvertingEncoderDecoderSupport} for
 	 * details.
-	 *
-	 * @param <T> The type that this Encoder can convert to.
+	 * @param <T> the type that this Encoder can convert to
 	 */
-	public static abstract class TextEncoder<T> extends
-			ConvertingEncoderDecoderSupport<T, String> implements Encoder.Text<T> {
+	public static abstract class TextEncoder<T> extends ConvertingEncoderDecoderSupport<T, String>
+			implements Encoder.Text<T> {
 	}
 
 
 	/**
 	 * A Text {@link javax.websocket.Encoder.Text javax.websocket.Encoder} that delegates
-	 * to Spring's conversion service. See {@link ConvertingEncoderDecoderSupport} for
-	 * details.
-	 *
-	 * @param <T> The type that this Decoder can convert from.
+	 * to Spring's conversion service. See {@link ConvertingEncoderDecoderSupport} for details.
+	 * @param <T> the type that this Decoder can convert from
 	 */
-	public static abstract class TextDecoder<T> extends
-			ConvertingEncoderDecoderSupport<T, String> implements Decoder.Text<T> {
+	public static abstract class TextDecoder<T> extends ConvertingEncoderDecoderSupport<T, String>
+			implements Decoder.Text<T> {
 	}
 
 }