SPR-8718 Prevent ClassCastException when the target of Converter<?,?> is a super-class of the actual target.

org.springframework.core/src/main/java/org/springframework/core/convert/support/GenericConversionService.java

@@ -485,7 +485,7 @@ public class GenericConversionService implements ConfigurableConversionService {
 	}
 	
 	@SuppressWarnings("unchecked")
-	private final class ConverterAdapter implements GenericConverter {
+	private final class ConverterAdapter implements ConditionalGenericConverter {
 
 		private final ConvertiblePair typeInfo;
 
@@ -500,6 +500,11 @@ public class GenericConversionService implements ConfigurableConversionService {
 			return Collections.singleton(this.typeInfo);
 		}
 
+		public boolean matches(TypeDescriptor sourceType, TypeDescriptor targetType) {
+			return (typeInfo.getTargetType().equals(targetType.getObjectType()) &&
+					typeInfo.getSourceType().isAssignableFrom(sourceType.getObjectType()));
+		}
+
 		public Object convert(Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {
 			if (source == null) {
 				return convertNullSource(sourceType, targetType);
@@ -511,6 +516,7 @@ public class GenericConversionService implements ConfigurableConversionService {
 			return this.typeInfo.getSourceType().getName() + " -> " + this.typeInfo.getTargetType().getName() +
 					" : " + this.converter.toString();
 		}
+
 	}
 
 

org.springframework.core/src/test/java/org/springframework/core/convert/support/GenericConversionServiceTests.java

@@ -16,6 +16,16 @@
 
 package org.springframework.core.convert.support;
 
+import static junit.framework.Assert.assertTrue;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertSame;
+import static org.junit.Assert.fail;
+
+import java.awt.Color;
+import java.awt.SystemColor;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
@@ -28,7 +38,6 @@ import java.util.Map;
 import java.util.Set;
 
 import org.junit.Test;
-
 import org.springframework.core.convert.ConversionFailedException;
 import org.springframework.core.convert.ConverterNotFoundException;
 import org.springframework.core.convert.TypeDescriptor;
@@ -39,14 +48,6 @@ import org.springframework.core.io.Resource;
 import org.springframework.util.StopWatch;
 import org.springframework.util.StringUtils;
 
-import static junit.framework.Assert.assertTrue;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertNull;
-import static org.junit.Assert.assertSame;
-import static org.junit.Assert.fail;
-
 /**
  * @author Keith Donald
  * @author Juergen Hoeller
@@ -205,6 +206,18 @@ public class GenericConversionServiceTests {
 		assertEquals(new Integer(3), result);
 	}
 
+	// SPR-8718
+	
+	@Test(expected=ConverterNotFoundException.class)
+	public void convertSuperTarget() {
+		conversionService.addConverter(new ColorConverter());
+		conversionService.convert("#000000", SystemColor.class);
+	}
+
+	public class ColorConverter implements Converter<String, Color> {
+		public Color convert(String source) { if (!source.startsWith("#")) source = "#" + source; return Color.decode(source); }
+	}
+
 	@Test
 	public void convertObjectToPrimitive() {
 		assertFalse(conversionService.canConvert(String.class, boolean.class));