diff --git a/spring-batch-infrastructure/src/main/java/org/springframework/batch/item/file/transform/DelimitedLineAggregator.java b/spring-batch-infrastructure/src/main/java/org/springframework/batch/item/file/transform/DelimitedLineAggregator.java
index e96bd5429..4d6c1a1c1 100644
--- a/spring-batch-infrastructure/src/main/java/org/springframework/batch/item/file/transform/DelimitedLineAggregator.java
+++ b/spring-batch-infrastructure/src/main/java/org/springframework/batch/item/file/transform/DelimitedLineAggregator.java
@@ -22,12 +22,12 @@ import org.springframework.util.StringUtils;
  * delimited list of strings. The default delimiter is a comma.
  * 
  * @author Dave Syer
- *
+ * 
  */
 public class DelimitedLineAggregator<T> extends ExtractorLineAggregator<T> {
 
 	private String delimiter = ",";
-	
+
 	/**
 	 * Public setter for the delimiter.
 	 * @param delimiter the delimiter to set
@@ -36,11 +36,9 @@ public class DelimitedLineAggregator<T> extends ExtractorLineAggregator<T> {
 		this.delimiter = delimiter;
 	}
 
-	/**
-	 * @see org.springframework.batch.item.file.transform.ExtractorLineAggregator#doAggregate(java.lang.Object[])
-	 */
-	public String doAggregate(Object[] item) {
-		return StringUtils.arrayToDelimitedString(item, this.delimiter);
+	@Override
+	public String doAggregate(Object[] fields) {
+		return StringUtils.arrayToDelimitedString(fields, this.delimiter);
 	}
 
 }
diff --git a/spring-batch-infrastructure/src/main/java/org/springframework/batch/item/file/transform/ExtractorLineAggregator.java b/spring-batch-infrastructure/src/main/java/org/springframework/batch/item/file/transform/ExtractorLineAggregator.java
index 2679492b0..a2277def7 100644
--- a/spring-batch-infrastructure/src/main/java/org/springframework/batch/item/file/transform/ExtractorLineAggregator.java
+++ b/spring-batch-infrastructure/src/main/java/org/springframework/batch/item/file/transform/ExtractorLineAggregator.java
@@ -43,13 +43,29 @@ public abstract class ExtractorLineAggregator<T> implements LineAggregator<T> {
 
 	/**
 	 * Extract fields from the given item using the {@link FieldExtractor} and
-	 * then aggregate them.  Null items are not allowed.
+	 * then aggregate them. Any null field returned by the extractor will be
+	 * replaced by an empty String. Null items are not allowed.
 	 * 
 	 * @see org.springframework.batch.item.file.transform.LineAggregator#aggregate(java.lang.Object)
 	 */
 	public String aggregate(T item) {
 		Assert.notNull(item);
-		return this.doAggregate(this.fieldExtractor.extract(item));
+		Object[] fields = this.fieldExtractor.extract(item);
+
+		//
+		// Replace nulls with empty strings
+		//
+		Object[] args = new Object[fields.length];
+		for (int i = 0; i < fields.length; i++) {
+			if (fields[i] == null) {
+				args[i] = "";
+			}
+			else {
+				args[i] = fields[i];
+			}
+		}
+
+		return this.doAggregate(args);
 	}
 
 	/**
diff --git a/spring-batch-infrastructure/src/main/java/org/springframework/batch/item/file/transform/FormatterLineAggregator.java b/spring-batch-infrastructure/src/main/java/org/springframework/batch/item/file/transform/FormatterLineAggregator.java
index 32bbf0df3..063df94dc 100644
--- a/spring-batch-infrastructure/src/main/java/org/springframework/batch/item/file/transform/FormatterLineAggregator.java
+++ b/spring-batch-infrastructure/src/main/java/org/springframework/batch/item/file/transform/FormatterLineAggregator.java
@@ -67,7 +67,6 @@ public class FormatterLineAggregator<T> extends ExtractorLineAggregator<T> {
 		this.format = format;
 	}
 
-
 	/**
 	 * Public setter for the locale.
 	 * @param locale the locale to set
@@ -76,9 +75,7 @@ public class FormatterLineAggregator<T> extends ExtractorLineAggregator<T> {
 		this.locale = locale;
 	}
 
-	/**
-	 * @see org.springframework.batch.item.file.transform.ExtractorLineAggregator#doAggregate(java.lang.Object[])
-	 */
+	@Override
 	protected String doAggregate(Object[] fields) {
 
 		Assert.notNull(format);
diff --git a/spring-batch-infrastructure/src/main/java/org/springframework/batch/item/file/transform/PassThroughFieldExtractor.java b/spring-batch-infrastructure/src/main/java/org/springframework/batch/item/file/transform/PassThroughFieldExtractor.java
index 773699609..06236d0f0 100644
--- a/spring-batch-infrastructure/src/main/java/org/springframework/batch/item/file/transform/PassThroughFieldExtractor.java
+++ b/spring-batch-infrastructure/src/main/java/org/springframework/batch/item/file/transform/PassThroughFieldExtractor.java
@@ -34,31 +34,13 @@ public class PassThroughFieldExtractor<T> implements FieldExtractor<T> {
 	public Object[] extract(T item) {
 
 		if (item.getClass().isArray()) {
-			Object[] items = (Object[]) item;
-			Object[] args = new Object[items.length];
-			for (int i = 0; i < items.length; i++) {
-				if (items[i] == null)
-					args[i] = "";
-				else
-					args[i] = items[i];
-			}
-			return args;
+			return (Object[]) item;
 		}
 
 		if (item instanceof Collection<?>) {
-			Collection<?> items = (Collection<?>) item;
-			Object[] args = new Object[items.size()];
-			int i = 0;
-			for (Object object : items) {
-				if (object == null)
-					args[i] = "";
-				else
-					args[i] = object;
-				i++;
-			}
-			return args;
+			return ((Collection<?>) item).toArray();
 		}
-		
+
 		if (item instanceof FieldSet) {
 			return ((FieldSet) item).getValues();
 		}
diff --git a/spring-batch-infrastructure/src/test/java/org/springframework/batch/item/file/transform/DelimitedLineAggregatorTests.java b/spring-batch-infrastructure/src/test/java/org/springframework/batch/item/file/transform/DelimitedLineAggregatorTests.java
index e14a86fa4..c390e6c7c 100644
--- a/spring-batch-infrastructure/src/test/java/org/springframework/batch/item/file/transform/DelimitedLineAggregatorTests.java
+++ b/spring-batch-infrastructure/src/test/java/org/springframework/batch/item/file/transform/DelimitedLineAggregatorTests.java
@@ -15,8 +15,9 @@
  */
 package org.springframework.batch.item.file.transform;
 
-import static org.junit.Assert.*;
+import static org.junit.Assert.assertEquals;
 
+import org.junit.Before;
 import org.junit.Test;
 
 /**
@@ -25,7 +26,19 @@ import org.junit.Test;
  */
 public class DelimitedLineAggregatorTests {
 
-	private DelimitedLineAggregator<String[]> aggregator = new DelimitedLineAggregator<String[]>();
+	private static DelimitedLineAggregator<String[]> aggregator;
+
+	private FieldExtractor<String[]> defaultFieldExtractor = new FieldExtractor<String[]>() {
+		public Object[] extract(String[] item) {
+			return item;
+		}
+	};
+
+	@Before
+	public void setup() {
+		aggregator = new DelimitedLineAggregator<String[]>();
+		aggregator.setFieldExtractor(defaultFieldExtractor);
+	}
 
 	@Test
 	public void testSetDelimiter() {
@@ -38,4 +51,8 @@ public class DelimitedLineAggregatorTests {
 		assertEquals("foo,bar", aggregator.aggregate(new String[] { "foo", "bar" }));
 	}
 
+	@Test
+	public void testAggregateWithNull() {
+		assertEquals("foo,,bar", aggregator.aggregate(new String[] { "foo", null, "bar" }));
+	}
 }
diff --git a/spring-batch-infrastructure/src/test/java/org/springframework/batch/item/file/transform/FormatterLineAggregatorTests.java b/spring-batch-infrastructure/src/test/java/org/springframework/batch/item/file/transform/FormatterLineAggregatorTests.java
index a5f0928c1..f284ae4c9 100644
--- a/spring-batch-infrastructure/src/test/java/org/springframework/batch/item/file/transform/FormatterLineAggregatorTests.java
+++ b/spring-batch-infrastructure/src/test/java/org/springframework/batch/item/file/transform/FormatterLineAggregatorTests.java
@@ -19,6 +19,7 @@ package org.springframework.batch.item.file.transform;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.fail;
 
+import org.junit.Before;
 import org.junit.Test;
 
 /**
@@ -29,7 +30,19 @@ import org.junit.Test;
 public class FormatterLineAggregatorTests {
 
 	// object under test
-	private FormatterLineAggregator<String[]> aggregator = new FormatterLineAggregator<String[]>();
+	private FormatterLineAggregator<String[]> aggregator;
+
+	private FieldExtractor<String[]> defaultFieldExtractor = new FieldExtractor<String[]>() {
+		public Object[] extract(String[] item) {
+			return item;
+		}
+	};
+
+	@Before
+	public void setup() {
+		aggregator = new FormatterLineAggregator<String[]>();
+		aggregator.setFieldExtractor(defaultFieldExtractor);
+	}
 
 	/**
 	 * If no ranges are specified, IllegalArgumentException is thrown
@@ -110,17 +123,18 @@ public class FormatterLineAggregatorTests {
 		aggregator.setMaximumLength(25);
 
 		aggregator.setFieldExtractor(new FieldExtractor<String[]>() {
-			private int[] widths = new int[] {13,12};
+			private int[] widths = new int[] { 13, 12 };
+
 			public Object[] extract(String[] item) {
 				String[] strings = new String[item.length];
 				for (int i = 0; i < strings.length; i++) {
 					strings[i] = item[i];
-					if (item[i].length()<widths[i]) {
+					if (item[i].length() < widths[i]) {
 						StringBuffer buffer = new StringBuffer(strings[i]);
-						for (int j = 0; j<(widths[i]-item[i].length()+1)/2; j++) {
+						for (int j = 0; j < (widths[i] - item[i].length() + 1) / 2; j++) {
 							buffer.append(" ");
 						}
-						strings[i] = buffer.toString(); 
+						strings[i] = buffer.toString();
 					}
 				}
 				return strings;
@@ -143,17 +157,18 @@ public class FormatterLineAggregatorTests {
 		aggregator.setMaximumLength(24);
 
 		aggregator.setFieldExtractor(new FieldExtractor<String[]>() {
-			private int[] widths = new int[] {13,11};
+			private int[] widths = new int[] { 13, 11 };
+
 			public Object[] extract(String[] item) {
 				String[] strings = new String[item.length];
 				for (int i = 0; i < strings.length; i++) {
 					strings[i] = item[i];
-					if (item[i].length()<widths[i]) {
+					if (item[i].length() < widths[i]) {
 						StringBuffer buffer = new StringBuffer(strings[i]);
-						for (int j = 0; j<widths[i]-item[i].length(); j++) {
+						for (int j = 0; j < widths[i] - item[i].length(); j++) {
 							buffer.append(".");
 						}
-						strings[i] = buffer.toString(); 
+						strings[i] = buffer.toString();
 					}
 				}
 				return strings;
@@ -181,8 +196,9 @@ public class FormatterLineAggregatorTests {
 	 */
 	@Test
 	public void testAggregateNullArgument() {
-		String[] args = { null };
-		aggregator.setFormat("%3s");
-		assertEquals("   ", aggregator.aggregate(args));
+		String[] args = { "foo", null, "bar" };
+		aggregator.setFormat("%3s%3s%3s");
+		assertEquals("foo   bar", aggregator.aggregate(args));
 	}
+
 }
diff --git a/spring-batch-infrastructure/src/test/java/org/springframework/batch/item/file/transform/PassThroughFieldExtractorTests.java b/spring-batch-infrastructure/src/test/java/org/springframework/batch/item/file/transform/PassThroughFieldExtractorTests.java
index 2ce00fec2..01998a915 100644
--- a/spring-batch-infrastructure/src/test/java/org/springframework/batch/item/file/transform/PassThroughFieldExtractorTests.java
+++ b/spring-batch-infrastructure/src/test/java/org/springframework/batch/item/file/transform/PassThroughFieldExtractorTests.java
@@ -39,7 +39,7 @@ public class PassThroughFieldExtractorTests {
 	public void testExtractArray() {
 		PassThroughFieldExtractor<String[]> extractor = new PassThroughFieldExtractor<String[]>();
 		Object[] result = extractor.extract(new String[] { "a", "b", null, "d" });
-		assertTrue(Arrays.equals(new Object[] { "a", "b", "", "d" }, result));
+		assertTrue(Arrays.equals(new Object[] { "a", "b", null, "d" }, result));
 	}
 
 	@Test
@@ -53,6 +53,6 @@ public class PassThroughFieldExtractorTests {
 	public void testExtractCollection() {
 		PassThroughFieldExtractor<List<String>> extractor = new PassThroughFieldExtractor<List<String>>();
 		Object[] result = extractor.extract(Arrays.asList("a", "b", null, "d"));
-		assertTrue(Arrays.equals(new Object[] { "a", "b", "", "d" }, result));
+		assertTrue(Arrays.equals(new Object[] { "a", "b", null, "d" }, result));
 	}
 }