diff --git a/spring-batch-infrastructure/src/main/java/org/springframework/batch/item/file/builder/FlatFileItemReaderBuilder.java b/spring-batch-infrastructure/src/main/java/org/springframework/batch/item/file/builder/FlatFileItemReaderBuilder.java
index e52d4dbde9..65a17c09a2 100644
--- a/spring-batch-infrastructure/src/main/java/org/springframework/batch/item/file/builder/FlatFileItemReaderBuilder.java
+++ b/spring-batch-infrastructure/src/main/java/org/springframework/batch/item/file/builder/FlatFileItemReaderBuilder.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2023 the original author or authors.
+ * Copyright 2016-2025 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -25,6 +25,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import java.util.function.Consumer;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
@@ -60,6 +61,7 @@
  * @author Drummond Dawson
  * @author Patrick Baumgartner
  * @author François Martin
+ * @author Daeho Kwon
  * @since 4.0
  * @see FlatFileItemReader
  */
@@ -89,9 +91,9 @@ public class FlatFileItemReaderBuilder<T> {
 
 	private LineTokenizer lineTokenizer;
 
-	private DelimitedBuilder<T> delimitedBuilder;
+	private DelimitedSpec<T> delimitedSpec;
 
-	private FixedLengthBuilder<T> fixedLengthBuilder;
+	private FixedLengthSpec<T> fixedLengthSpec;
 
 	private Class<T> targetType;
 
@@ -306,30 +308,56 @@ public FlatFileItemReaderBuilder<T> lineTokenizer(LineTokenizer tokenizer) {
 	}
 
 	/**
-	 * Returns an instance of a {@link DelimitedBuilder} for building a
+	 * Returns an instance of a {@link DelimitedSpec} for building a
 	 * {@link DelimitedLineTokenizer}. The {@link DelimitedLineTokenizer} configured by
 	 * this builder will only be used if one is not explicitly configured via
 	 * {@link FlatFileItemReaderBuilder#lineTokenizer}
-	 * @return a {@link DelimitedBuilder}
+	 * @return a {@link DelimitedSpec}
 	 *
 	 */
-	public DelimitedBuilder<T> delimited() {
-		this.delimitedBuilder = new DelimitedBuilder<>(this);
-		updateTokenizerValidation(this.delimitedBuilder, 1);
-		return this.delimitedBuilder;
+	public DelimitedSpec<T> delimited() {
+		this.delimitedSpec = new DelimitedSpec<>(this);
+		updateTokenizerValidation(this.delimitedSpec, 1);
+		return this.delimitedSpec;
 	}
 
 	/**
-	 * Returns an instance of a {@link FixedLengthBuilder} for building a
+	 * Configure a {@link DelimitedSpec} using a lambda.
+	 * @param consumer the spec to configure
+	 * @return the current builder instance
+	 */
+	public FlatFileItemReaderBuilder<T> delimited(Consumer<DelimitedSpec<T>> consumer) {
+		DelimitedSpec<T> builder = new DelimitedSpec<>(this);
+		consumer.accept(builder);
+		this.delimitedSpec = builder;
+		updateTokenizerValidation(this.delimitedSpec, 1);
+		return this;
+	}
+
+	/**
+	 * Returns an instance of a {@link FixedLengthSpec} for building a
 	 * {@link FixedLengthTokenizer}. The {@link FixedLengthTokenizer} configured by this
 	 * builder will only be used if the {@link FlatFileItemReaderBuilder#lineTokenizer}
 	 * has not been configured.
-	 * @return a {@link FixedLengthBuilder}
+	 * @return a {@link FixedLengthSpec}
 	 */
-	public FixedLengthBuilder<T> fixedLength() {
-		this.fixedLengthBuilder = new FixedLengthBuilder<>(this);
-		updateTokenizerValidation(this.fixedLengthBuilder, 2);
-		return this.fixedLengthBuilder;
+	public FixedLengthSpec<T> fixedLength() {
+		this.fixedLengthSpec = new FixedLengthSpec<>(this);
+		updateTokenizerValidation(this.fixedLengthSpec, 2);
+		return this.fixedLengthSpec;
+	}
+
+	/**
+	 * Configure a {@link FixedLengthSpec} using a lambda.
+	 * @param consumer the spec to configure
+	 * @return the current builder instance
+	 */
+	public FlatFileItemReaderBuilder<T> fixedLength(Consumer<FixedLengthSpec<T>> consumer) {
+		FixedLengthSpec<T> builder = new FixedLengthSpec<>(this);
+		consumer.accept(builder);
+		this.fixedLengthSpec = builder;
+		updateTokenizerValidation(this.fixedLengthSpec, 2);
+		return this;
 	}
 
 	/**
@@ -451,11 +479,11 @@ public FlatFileItemReader<T> build() {
 			if (this.lineTokenizer != null) {
 				lineMapper.setLineTokenizer(this.lineTokenizer);
 			}
-			else if (this.fixedLengthBuilder != null) {
-				lineMapper.setLineTokenizer(this.fixedLengthBuilder.build());
+			else if (this.fixedLengthSpec != null) {
+				lineMapper.setLineTokenizer(this.fixedLengthSpec.build());
 			}
-			else if (this.delimitedBuilder != null) {
-				lineMapper.setLineTokenizer(this.delimitedBuilder.build());
+			else if (this.delimitedSpec != null) {
+				lineMapper.setLineTokenizer(this.delimitedSpec.build());
 			}
 			else {
 				throw new IllegalStateException("No LineTokenizer implementation was provided.");
@@ -524,7 +552,7 @@ private void updateTokenizerValidation(Object tokenizer, int index) {
 	 *
 	 * @param <T> the type of the parent {@link FlatFileItemReaderBuilder}
 	 */
-	public static class DelimitedBuilder<T> {
+	public static class DelimitedSpec<T> {
 
 		private final FlatFileItemReaderBuilder<T> parent;
 
@@ -540,7 +568,7 @@ public static class DelimitedBuilder<T> {
 
 		private boolean strict = true;
 
-		protected DelimitedBuilder(FlatFileItemReaderBuilder<T> parent) {
+		protected DelimitedSpec(FlatFileItemReaderBuilder<T> parent) {
 			this.parent = parent;
 		}
 
@@ -550,7 +578,7 @@ protected DelimitedBuilder(FlatFileItemReaderBuilder<T> parent) {
 		 * @return The instance of the builder for chaining.
 		 * @see DelimitedLineTokenizer#setDelimiter(String)
 		 */
-		public DelimitedBuilder<T> delimiter(String delimiter) {
+		public DelimitedSpec<T> delimiter(String delimiter) {
 			this.delimiter = delimiter;
 			return this;
 		}
@@ -561,7 +589,7 @@ public DelimitedBuilder<T> delimiter(String delimiter) {
 		 * @return The instance of the builder for chaining.
 		 * @see DelimitedLineTokenizer#setQuoteCharacter(char)
 		 */
-		public DelimitedBuilder<T> quoteCharacter(char quoteCharacter) {
+		public DelimitedSpec<T> quoteCharacter(char quoteCharacter) {
 			this.quoteCharacter = quoteCharacter;
 			return this;
 		}
@@ -572,7 +600,7 @@ public DelimitedBuilder<T> quoteCharacter(char quoteCharacter) {
 		 * @return The instance of the builder for chaining.
 		 * @see DelimitedLineTokenizer#setIncludedFields(int[])
 		 */
-		public DelimitedBuilder<T> includedFields(Integer... fields) {
+		public DelimitedSpec<T> includedFields(Integer... fields) {
 			this.includedFields.addAll(Arrays.asList(fields));
 			return this;
 		}
@@ -583,7 +611,7 @@ public DelimitedBuilder<T> includedFields(Integer... fields) {
 		 * @return The instance of the builder for chaining.
 		 * @see DelimitedLineTokenizer#setIncludedFields(int[])
 		 */
-		public DelimitedBuilder<T> addIncludedField(int field) {
+		public DelimitedSpec<T> addIncludedField(int field) {
 			this.includedFields.add(field);
 			return this;
 		}
@@ -597,7 +625,7 @@ public DelimitedBuilder<T> addIncludedField(int field) {
 		 * @return The instance of the builder for chaining.
 		 * @see DelimitedLineTokenizer#setFieldSetFactory(FieldSetFactory)
 		 */
-		public DelimitedBuilder<T> fieldSetFactory(FieldSetFactory fieldSetFactory) {
+		public DelimitedSpec<T> fieldSetFactory(FieldSetFactory fieldSetFactory) {
 			this.fieldSetFactory = fieldSetFactory;
 			return this;
 		}
@@ -623,7 +651,7 @@ public FlatFileItemReaderBuilder<T> names(String... names) {
 		 * @since 5.1
 		 * @param strict the strict flag to set
 		 */
-		public DelimitedBuilder<T> strict(boolean strict) {
+		public DelimitedSpec<T> strict(boolean strict) {
 			this.strict = strict;
 			return this;
 		}
@@ -682,7 +710,7 @@ public DelimitedLineTokenizer build() {
 	 *
 	 * @param <T> the type of the parent {@link FlatFileItemReaderBuilder}
 	 */
-	public static class FixedLengthBuilder<T> {
+	public static class FixedLengthSpec<T> {
 
 		private final FlatFileItemReaderBuilder<T> parent;
 
@@ -694,7 +722,7 @@ public static class FixedLengthBuilder<T> {
 
 		private FieldSetFactory fieldSetFactory = new DefaultFieldSetFactory();
 
-		protected FixedLengthBuilder(FlatFileItemReaderBuilder<T> parent) {
+		protected FixedLengthSpec(FlatFileItemReaderBuilder<T> parent) {
 			this.parent = parent;
 		}
 
@@ -704,7 +732,7 @@ protected FixedLengthBuilder(FlatFileItemReaderBuilder<T> parent) {
 		 * @return This instance for chaining
 		 * @see FixedLengthTokenizer#setColumns(Range[])
 		 */
-		public FixedLengthBuilder<T> columns(Range... ranges) {
+		public FixedLengthSpec<T> columns(Range... ranges) {
 			this.ranges.addAll(Arrays.asList(ranges));
 			return this;
 		}
@@ -715,7 +743,7 @@ public FixedLengthBuilder<T> columns(Range... ranges) {
 		 * @return This instance for chaining
 		 * @see FixedLengthTokenizer#setColumns(Range[])
 		 */
-		public FixedLengthBuilder<T> addColumns(Range range) {
+		public FixedLengthSpec<T> addColumns(Range range) {
 			this.ranges.add(range);
 			return this;
 		}
@@ -727,7 +755,7 @@ public FixedLengthBuilder<T> addColumns(Range range) {
 		 * @return This instance for chaining
 		 * @see FixedLengthTokenizer#setColumns(Range[])
 		 */
-		public FixedLengthBuilder<T> addColumns(Range range, int index) {
+		public FixedLengthSpec<T> addColumns(Range range, int index) {
 			this.ranges.add(index, range);
 			return this;
 		}
@@ -750,7 +778,7 @@ public FlatFileItemReaderBuilder<T> names(String... names) {
 		 * @return This instance for chaining
 		 * @see FixedLengthTokenizer#setStrict(boolean)
 		 */
-		public FixedLengthBuilder<T> strict(boolean strict) {
+		public FixedLengthSpec<T> strict(boolean strict) {
 			this.strict = strict;
 			return this;
 		}
@@ -764,7 +792,7 @@ public FixedLengthBuilder<T> strict(boolean strict) {
 		 * @return The instance of the builder for chaining.
 		 * @see FixedLengthTokenizer#setFieldSetFactory(FieldSetFactory)
 		 */
-		public FixedLengthBuilder<T> fieldSetFactory(FieldSetFactory fieldSetFactory) {
+		public FixedLengthSpec<T> fieldSetFactory(FieldSetFactory fieldSetFactory) {
 			this.fieldSetFactory = fieldSetFactory;
 			return this;
 		}
diff --git a/spring-batch-infrastructure/src/main/java/org/springframework/batch/item/file/builder/FlatFileItemWriterBuilder.java b/spring-batch-infrastructure/src/main/java/org/springframework/batch/item/file/builder/FlatFileItemWriterBuilder.java
index 7de7de5301..6e1954afcc 100644
--- a/spring-batch-infrastructure/src/main/java/org/springframework/batch/item/file/builder/FlatFileItemWriterBuilder.java
+++ b/spring-batch-infrastructure/src/main/java/org/springframework/batch/item/file/builder/FlatFileItemWriterBuilder.java
@@ -19,6 +19,7 @@
 import java.util.Arrays;
 import java.util.List;
 import java.util.Locale;
+import java.util.function.Consumer;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
@@ -43,6 +44,7 @@
  * @author Glenn Renfro
  * @author Mahmoud Ben Hassine
  * @author Drummond Dawson
+ * @author Daeho Kwon
  * @since 4.0
  * @see FlatFileItemWriter
  */
@@ -76,9 +78,9 @@ public class FlatFileItemWriterBuilder<T> {
 
 	private String name;
 
-	private DelimitedBuilder<T> delimitedBuilder;
+	private DelimitedSpec<T> delimitedSpec;
 
-	private FormattedBuilder<T> formattedBuilder;
+	private FormattedSpec<T> formattedSpec;
 
 	/**
 	 * Configure if the state of the
@@ -246,29 +248,53 @@ public FlatFileItemWriterBuilder<T> transactional(boolean transactional) {
 	}
 
 	/**
-	 * Returns an instance of a {@link DelimitedBuilder} for building a
+	 * Returns an instance of a {@link DelimitedSpec} for building a
 	 * {@link DelimitedLineAggregator}. The {@link DelimitedLineAggregator} configured by
 	 * this builder will only be used if one is not explicitly configured via
 	 * {@link FlatFileItemWriterBuilder#lineAggregator}
-	 * @return a {@link DelimitedBuilder}
+	 * @return a {@link DelimitedSpec}
 	 *
 	 */
-	public DelimitedBuilder<T> delimited() {
-		this.delimitedBuilder = new DelimitedBuilder<>(this);
-		return this.delimitedBuilder;
+	public DelimitedSpec<T> delimited() {
+		this.delimitedSpec = new DelimitedSpec<>(this);
+		return this.delimitedSpec;
 	}
 
 	/**
-	 * Returns an instance of a {@link FormattedBuilder} for building a
+	 * Configure a {@link DelimitedSpec} using a lambda.
+	 * @param consumer the spec to configure
+	 * @return the current builder instance
+	 */
+	public FlatFileItemWriterBuilder<T> delimited(Consumer<DelimitedSpec<T>> consumer) {
+		DelimitedSpec<T> builder = new DelimitedSpec<>(this);
+		consumer.accept(builder);
+		this.delimitedSpec = builder;
+		return this;
+	}
+
+	/**
+	 * Returns an instance of a {@link FormattedSpec} for building a
 	 * {@link FormatterLineAggregator}. The {@link FormatterLineAggregator} configured by
 	 * this builder will only be used if one is not explicitly configured via
 	 * {@link FlatFileItemWriterBuilder#lineAggregator}
-	 * @return a {@link FormattedBuilder}
+	 * @return a {@link FormattedSpec}
 	 *
 	 */
-	public FormattedBuilder<T> formatted() {
-		this.formattedBuilder = new FormattedBuilder<>(this);
-		return this.formattedBuilder;
+	public FormattedSpec<T> formatted() {
+		this.formattedSpec = new FormattedSpec<>(this);
+		return this.formattedSpec;
+	}
+
+	/**
+	 * Configure a {@link FormattedSpec} using a lambda.
+	 * @param consumer the spec to configure
+	 * @return the current builder instance
+	 */
+	public FlatFileItemWriterBuilder<T> formatted(Consumer<FormattedSpec<T>> consumer) {
+		FormattedSpec<T> builder = new FormattedSpec<>(this);
+		consumer.accept(builder);
+		this.formattedSpec = builder;
+		return this;
 	}
 
 	/**
@@ -276,7 +302,7 @@ public FormattedBuilder<T> formatted() {
 	 *
 	 * @param <T> the type of the parent {@link FlatFileItemWriterBuilder}
 	 */
-	public static class FormattedBuilder<T> {
+	public static class FormattedSpec<T> {
 
 		private final FlatFileItemWriterBuilder<T> parent;
 
@@ -294,7 +320,7 @@ public static class FormattedBuilder<T> {
 
 		private Class<T> sourceType;
 
-		protected FormattedBuilder(FlatFileItemWriterBuilder<T> parent) {
+		protected FormattedSpec(FlatFileItemWriterBuilder<T> parent) {
 			this.parent = parent;
 		}
 
@@ -303,7 +329,7 @@ protected FormattedBuilder(FlatFileItemWriterBuilder<T> parent) {
 		 * @param format used to aggregate items
 		 * @return The instance of the builder for chaining.
 		 */
-		public FormattedBuilder<T> format(String format) {
+		public FormattedSpec<T> format(String format) {
 			this.format = format;
 			return this;
 		}
@@ -313,7 +339,7 @@ public FormattedBuilder<T> format(String format) {
 		 * @param locale to use
 		 * @return The instance of the builder for chaining.
 		 */
-		public FormattedBuilder<T> locale(Locale locale) {
+		public FormattedSpec<T> locale(Locale locale) {
 			this.locale = locale;
 			return this;
 		}
@@ -324,7 +350,7 @@ public FormattedBuilder<T> locale(Locale locale) {
 		 * @param minimumLength of the formatted string
 		 * @return The instance of the builder for chaining.
 		 */
-		public FormattedBuilder<T> minimumLength(int minimumLength) {
+		public FormattedSpec<T> minimumLength(int minimumLength) {
 			this.minimumLength = minimumLength;
 			return this;
 		}
@@ -335,7 +361,7 @@ public FormattedBuilder<T> minimumLength(int minimumLength) {
 		 * @param maximumLength of the formatted string
 		 * @return The instance of the builder for chaining.
 		 */
-		public FormattedBuilder<T> maximumLength(int maximumLength) {
+		public FormattedSpec<T> maximumLength(int maximumLength) {
 			this.maximumLength = maximumLength;
 			return this;
 		}
@@ -348,7 +374,7 @@ public FormattedBuilder<T> maximumLength(int maximumLength) {
 		 * @return The current instance of the builder.
 		 * @since 5.0
 		 */
-		public FormattedBuilder<T> sourceType(Class<T> sourceType) {
+		public FormattedSpec<T> sourceType(Class<T> sourceType) {
 			this.sourceType = sourceType;
 
 			return this;
@@ -368,7 +394,7 @@ public FlatFileItemWriterBuilder<T> fieldExtractor(FieldExtractor<T> fieldExtrac
 		 * Names of each of the fields within the fields that are returned in the order
 		 * they occur within the formatted file. These names will be used to create a
 		 * {@link BeanWrapperFieldExtractor} only if no explicit field extractor is set
-		 * via {@link FormattedBuilder#fieldExtractor(FieldExtractor)}.
+		 * via {@link FormattedSpec#fieldExtractor(FieldExtractor)}.
 		 * @param names names of each field
 		 * @return The parent {@link FlatFileItemWriterBuilder}
 		 * @see BeanWrapperFieldExtractor#setNames(String[])
@@ -417,7 +443,7 @@ public FormatterLineAggregator<T> build() {
 	 *
 	 * @param <T> the type of the parent {@link FlatFileItemWriterBuilder}
 	 */
-	public static class DelimitedBuilder<T> {
+	public static class DelimitedSpec<T> {
 
 		private final FlatFileItemWriterBuilder<T> parent;
 
@@ -431,7 +457,7 @@ public static class DelimitedBuilder<T> {
 
 		private Class<T> sourceType;
 
-		protected DelimitedBuilder(FlatFileItemWriterBuilder<T> parent) {
+		protected DelimitedSpec(FlatFileItemWriterBuilder<T> parent) {
 			this.parent = parent;
 		}
 
@@ -441,7 +467,7 @@ protected DelimitedBuilder(FlatFileItemWriterBuilder<T> parent) {
 		 * @return The instance of the builder for chaining.
 		 * @see DelimitedLineAggregator#setDelimiter(String)
 		 */
-		public DelimitedBuilder<T> delimiter(String delimiter) {
+		public DelimitedSpec<T> delimiter(String delimiter) {
 			this.delimiter = delimiter;
 			return this;
 		}
@@ -454,7 +480,7 @@ public DelimitedBuilder<T> delimiter(String delimiter) {
 		 * @return The current instance of the builder.
 		 * @since 5.0
 		 */
-		public DelimitedBuilder<T> sourceType(Class<T> sourceType) {
+		public DelimitedSpec<T> sourceType(Class<T> sourceType) {
 			this.sourceType = sourceType;
 
 			return this;
@@ -467,7 +493,7 @@ public DelimitedBuilder<T> sourceType(Class<T> sourceType) {
 		 * @see DelimitedLineAggregator#setQuoteCharacter(String)
 		 * @since 5.1
 		 */
-		public DelimitedBuilder<T> quoteCharacter(String quoteCharacter) {
+		public DelimitedSpec<T> quoteCharacter(String quoteCharacter) {
 			this.quoteCharacter = quoteCharacter;
 			return this;
 		}
@@ -476,7 +502,7 @@ public DelimitedBuilder<T> quoteCharacter(String quoteCharacter) {
 		 * Names of each of the fields within the fields that are returned in the order
 		 * they occur within the delimited file. These names will be used to create a
 		 * {@link BeanWrapperFieldExtractor} only if no explicit field extractor is set
-		 * via {@link DelimitedBuilder#fieldExtractor(FieldExtractor)}.
+		 * via {@link DelimitedSpec#fieldExtractor(FieldExtractor)}.
 		 * @param names names of each field
 		 * @return The parent {@link FlatFileItemWriterBuilder}
 		 * @see BeanWrapperFieldExtractor#setNames(String[])
@@ -537,8 +563,8 @@ public DelimitedLineAggregator<T> build() {
 	 */
 	public FlatFileItemWriter<T> build() {
 
-		Assert.isTrue(this.lineAggregator != null || this.delimitedBuilder != null || this.formattedBuilder != null,
-				"A LineAggregator or a DelimitedBuilder or a FormattedBuilder is required");
+		Assert.isTrue(this.lineAggregator != null || this.delimitedSpec != null || this.formattedSpec != null,
+				"A LineAggregator or a DelimitedSpec or a FormattedSpec is required");
 
 		if (this.saveState) {
 			Assert.hasText(this.name, "A name is required when saveState is true");
@@ -558,13 +584,13 @@ public FlatFileItemWriter<T> build() {
 		writer.setForceSync(this.forceSync);
 		writer.setHeaderCallback(this.headerCallback);
 		if (this.lineAggregator == null) {
-			Assert.state(this.delimitedBuilder == null || this.formattedBuilder == null,
+			Assert.state(this.delimitedSpec == null || this.formattedSpec == null,
 					"Either a DelimitedLineAggregator or a FormatterLineAggregator should be provided, but not both");
-			if (this.delimitedBuilder != null) {
-				this.lineAggregator = this.delimitedBuilder.build();
+			if (this.delimitedSpec != null) {
+				this.lineAggregator = this.delimitedSpec.build();
 			}
 			else {
-				this.lineAggregator = this.formattedBuilder.build();
+				this.lineAggregator = this.formattedSpec.build();
 			}
 		}
 		writer.setLineAggregator(this.lineAggregator);
diff --git a/spring-batch-infrastructure/src/test/java/org/springframework/batch/item/file/builder/FlatFileItemReaderBuilderTests.java b/spring-batch-infrastructure/src/test/java/org/springframework/batch/item/file/builder/FlatFileItemReaderBuilderTests.java
index 3e824f4a96..194ddd2161 100644
--- a/spring-batch-infrastructure/src/test/java/org/springframework/batch/item/file/builder/FlatFileItemReaderBuilderTests.java
+++ b/spring-batch-infrastructure/src/test/java/org/springframework/batch/item/file/builder/FlatFileItemReaderBuilderTests.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2023 the original author or authors.
+ * Copyright 2016-2025 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -57,8 +57,10 @@
  * @author Mahmoud Ben Hassine
  * @author Drummond Dawson
  * @author Glenn Renfro
+ * @author Daeho Kwon
  * @author Patrick Baumgartner
  * @author François Martin
+ * @author Daeho Kwon
  */
 class FlatFileItemReaderBuilderTests {
 
@@ -628,6 +630,39 @@ class Person {
 		assertInstanceOf(BeanWrapperFieldSetMapper.class, fieldSetMapper);
 	}
 
+	@Test
+	void testDelimitedBuilderLambda() throws Exception {
+		FlatFileItemReader<Foo> reader = new FlatFileItemReaderBuilder<Foo>().name("fooReader")
+			.resource(getResource("1,2,3"))
+			.delimited(config -> config.delimiter(",").names("first", "second", "third"))
+			.targetType(Foo.class)
+			.build();
+
+		reader.open(new ExecutionContext());
+		Foo item = reader.read();
+		assertEquals(1, item.getFirst());
+		assertEquals(2, item.getSecond());
+		assertEquals("3", item.getThird());
+		assertNull(reader.read());
+	}
+
+	@Test
+	void testFixedLengthBuilderLambda() throws Exception {
+		FlatFileItemReader<Foo> reader = new FlatFileItemReaderBuilder<Foo>().name("fooReader")
+			.resource(getResource("1  2  3"))
+			.fixedLength(config -> config.columns(new Range(1, 3), new Range(4, 6), new Range(7))
+				.names("first", "second", "third"))
+			.targetType(Foo.class)
+			.build();
+
+		reader.open(new ExecutionContext());
+		Foo item = reader.read();
+		assertEquals(1, item.getFirst());
+		assertEquals(2, item.getSecond());
+		assertEquals("3", item.getThird());
+		assertNull(reader.read());
+	}
+
 	private Resource getResource(String contents) {
 		return new ByteArrayResource(contents.getBytes());
 	}
diff --git a/spring-batch-infrastructure/src/test/java/org/springframework/batch/item/file/builder/FlatFileItemWriterBuilderTests.java b/spring-batch-infrastructure/src/test/java/org/springframework/batch/item/file/builder/FlatFileItemWriterBuilderTests.java
index ad8083c4d2..63ca71b4ec 100644
--- a/spring-batch-infrastructure/src/test/java/org/springframework/batch/item/file/builder/FlatFileItemWriterBuilderTests.java
+++ b/spring-batch-infrastructure/src/test/java/org/springframework/batch/item/file/builder/FlatFileItemWriterBuilderTests.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2023 the original author or authors.
+ * Copyright 2016-2025 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -48,6 +48,7 @@
  * @author Mahmoud Ben Hassine
  * @author Drummond Dawson
  * @author Glenn Renfro
+ * @author Daeho Kwon
  */
 class FlatFileItemWriterBuilderTests {
 
@@ -236,6 +237,32 @@ void testDelimitedOutputWithCustomFieldExtractor() throws Exception {
 		assertEquals("HEADER$1 3$4 6$FOOTER", readLine("UTF-16LE", output));
 	}
 
+	@Test
+	void testDelimitedWithLambda() throws Exception {
+
+		WritableResource output = new FileSystemResource(File.createTempFile("foo", "txt"));
+
+		FlatFileItemWriter<Foo> writer = new FlatFileItemWriterBuilder<Foo>().name("foo")
+			.resource(output)
+			.lineSeparator("$")
+			.delimited(config -> config.delimiter(" ")
+				.fieldExtractor(item -> new Object[] { item.getFirst(), item.getThird() }))
+			.encoding("UTF-16LE")
+			.headerCallback(writer1 -> writer1.append("HEADER"))
+			.footerCallback(writer12 -> writer12.append("FOOTER"))
+			.build();
+
+		ExecutionContext executionContext = new ExecutionContext();
+
+		writer.open(executionContext);
+
+		writer.write(Chunk.of(new Foo(1, 2, "3"), new Foo(4, 5, "6")));
+
+		writer.close();
+
+		assertEquals("HEADER$1 3$4 6$FOOTER", readLine("UTF-16LE", output));
+	}
+
 	@Test
 	void testFormattedOutputWithDefaultFieldExtractor() throws Exception {
 
@@ -290,6 +317,32 @@ void testFormattedOutputWithCustomFieldExtractor() throws Exception {
 		assertEquals("HEADER$  1  3$  4  6$FOOTER", readLine("UTF-16LE", output));
 	}
 
+	@Test
+	void testFormattedWithLambda() throws Exception {
+
+		WritableResource output = new FileSystemResource(File.createTempFile("foo", "txt"));
+
+		FlatFileItemWriter<Foo> writer = new FlatFileItemWriterBuilder<Foo>().name("foo")
+			.resource(output)
+			.lineSeparator("$")
+			.formatted(config -> config.format("%3s%3s")
+				.fieldExtractor(item -> new Object[] { item.getFirst(), item.getThird() }))
+			.encoding("UTF-16LE")
+			.headerCallback(writer1 -> writer1.append("HEADER"))
+			.footerCallback(writer12 -> writer12.append("FOOTER"))
+			.build();
+
+		ExecutionContext executionContext = new ExecutionContext();
+
+		writer.open(executionContext);
+
+		writer.write(Chunk.of(new Foo(1, 2, "3"), new Foo(4, 5, "6")));
+
+		writer.close();
+
+		assertEquals("HEADER$  1  3$  4  6$FOOTER", readLine("UTF-16LE", output));
+	}
+
 	@Test
 	void testFlags() throws Exception {