Minor refactoring

* Remove unneeded exception declarations
* Collapse catch blocks
* Replace string concatenation with builder append

Author: scordio

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/file/mapping/BeanWrapperFieldSetMapper.java

@@ -246,10 +246,7 @@ private T getBean() {
 		try {
 			return type.newInstance();
 		}
-		catch (InstantiationException e) {
-			ReflectionUtils.handleReflectionException(e);
-		}
-		catch (IllegalAccessException e) {
+		catch (InstantiationException | IllegalAccessException e) {
 			ReflectionUtils.handleReflectionException(e);
 		}
 		// should not happen
@@ -370,10 +367,7 @@ private Object getPropertyValue(Object bean, String nestedName) {
 				nestedValue = wrapper.getPropertyType(nestedName).newInstance();
 				wrapper.setPropertyValue(nestedName, nestedValue);
 			}
-			catch (InstantiationException e) {
-				ReflectionUtils.handleReflectionException(e);
-			}
-			catch (IllegalAccessException e) {
+			catch (InstantiationException | IllegalAccessException e) {
 				ReflectionUtils.handleReflectionException(e);
 			}
 		}

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/file/transform/RecursiveCollectionLineAggregator.java

@@ -30,7 +30,7 @@ public class RecursiveCollectionLineAggregator<T> implements LineAggregator<Coll
 
 	private static final String LINE_SEPARATOR = System.getProperty("line.separator");
 
-	private LineAggregator<T> delegate = new PassThroughLineAggregator<T>();
+	private LineAggregator<T> delegate = new PassThroughLineAggregator<>();
 
 	/**
 	 * Public setter for the {@link LineAggregator} to use on single items, that
@@ -47,13 +47,13 @@ public void setDelegate(LineAggregator<T> delegate) {
 	 * (non-Javadoc)
 	 * @see org.springframework.batch.item.file.transform.LineAggregator#aggregate(java.lang.Object)
 	 */
-    @Override
+	@Override
 	public String aggregate(Collection<T> items) {
 		StringBuilder builder = new StringBuilder();
 		for (T value : items) {
-			builder.append(delegate.aggregate(value) + LINE_SEPARATOR);
+			builder.append(delegate.aggregate(value)).append(LINE_SEPARATOR);
 		}
-		return builder.delete(builder.length()-LINE_SEPARATOR.length(),builder.length()).toString();
+		return builder.delete(builder.length() - LINE_SEPARATOR.length(), builder.length()).toString();
 	}
 
 }

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/support/IteratorItemReader.java

@@ -64,7 +64,7 @@ public IteratorItemReader(Iterator<T> iterator) {
 	 * iterator provided.
 	 */
     @Override
-	public T read() throws Exception, UnexpectedInputException, ParseException {
+	public T read() {
 		if (iterator.hasNext())
 			return iterator.next();
 		else