polish

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

@@ -150,7 +150,7 @@ public class GenericConversionService implements ConversionService, ConverterReg
 		Assert.notNull(sourceType, "The source type to convert to is required");
 		Assert.notNull(targetType, "The targetType to convert to is required");
 		if (source == null) {
-			return null;
+			return convertNull(sourceType, targetType);
 		}
 		Assert.isTrue(sourceType != TypeDescriptor.NULL,
 				"The source TypeDescriptor must not be TypeDescriptor.NULL when source != null");
@@ -197,6 +197,10 @@ public class GenericConversionService implements ConversionService, ConverterReg
 		getSourceMap(sourceType).put(targetType, converter);
 	}
 
+	protected Object convertNull(TypeDescriptor sourceType, TypeDescriptor targetType) {
+		return null;
+	}
+	
 	protected GenericConverter getConverter(TypeDescriptor sourceType, TypeDescriptor targetType) {
 		return findConverterByClassPair(sourceType.getObjectType(), targetType.getObjectType());
 	}

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

@@ -29,14 +29,14 @@ class ObjectToArrayGenericConverter implements GenericConverter {
 	
 	public Object convert(Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {
 		TypeDescriptor targetElementType = targetType.getElementTypeDescriptor();
-		Object array = Array.newInstance(targetType.getElementType(), 1);
+		Object target = Array.newInstance(targetElementType.getType(), 1);
 		if (sourceType.isAssignableTo(targetElementType)) {
-			Array.set(array, 0, source);			
+			Array.set(target, 0, source);			
 		} else {
 			GenericConverter converter = conversionService.getConverter(sourceType, targetElementType);
-			Array.set(array, 0, converter.convert(source, sourceType, targetElementType));
+			Array.set(target, 0, converter.convert(source, sourceType, targetElementType));
 		}
-		return array;
+		return target;
 	}
 
 }

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

@@ -15,6 +15,9 @@
  */
 package org.springframework.core.convert.support;
 
+import java.util.Collection;
+
+import org.springframework.core.CollectionFactory;
 import org.springframework.core.convert.TypeDescriptor;
 
 class ObjectToCollectionGenericConverter implements GenericConverter {
@@ -26,7 +29,15 @@ class ObjectToCollectionGenericConverter implements GenericConverter {
 	}
 	
 	public Object convert(Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {
-		throw new UnsupportedOperationException("Not yet implemented");
+		Collection target = CollectionFactory.createCollection(targetType.getType(), 1);
+		TypeDescriptor targetElementType = targetType.getElementTypeDescriptor();
+		if (targetElementType == TypeDescriptor.NULL || sourceType.isAssignableTo(targetElementType)) {
+			target.add(source);
+		} else {
+			GenericConverter converter = conversionService.getConverter(sourceType, targetElementType);
+			target.add(converter.convert(source, sourceType, targetElementType));
+		}
+		return target;
 	}
 
-}
+}