Avoid ByteArrayResource fallback when JsonItemReaderBuilder resource is null

Resolves #5234

Signed-off-by: banseok1216 <bansuk1216@naver.com>

Author: banseok1216

spring-batch-infrastructure/src/main/java/org/springframework/batch/infrastructure/item/json/JsonItemReader.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2018-2025 the original author or authors.
+ * Copyright 2018-present 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.
@@ -55,12 +55,22 @@ public class JsonItemReader<T> extends AbstractItemCountingItemStreamItemReader<
 
 	private static final Log LOGGER = LogFactory.getLog(JsonItemReader.class);
 
-	private Resource resource;
+	private @Nullable Resource resource;
 
 	private JsonObjectReader<T> jsonObjectReader;
 
 	private boolean strict = true;
 
+	/**
+	 * Create a new {@link JsonItemReader} instance.
+	 * @param jsonObjectReader the json object reader to use
+	 * @since 6.0.4
+	 */
+	public JsonItemReader(JsonObjectReader<T> jsonObjectReader) {
+		Assert.notNull(jsonObjectReader, "The json object reader must not be null.");
+		this.jsonObjectReader = jsonObjectReader;
+	}
+
 	/**
 	 * Create a new {@link JsonItemReader} instance.
 	 * @param resource the input json resource
@@ -92,7 +102,7 @@ public void setStrict(boolean strict) {
 	}
 
 	@Override
-	public void setResource(Resource resource) {
+	public void setResource(@Nullable Resource resource) {
 		this.resource = resource;
 	}
 
@@ -103,6 +113,8 @@ public void setResource(Resource resource) {
 
 	@Override
 	protected void doOpen() throws Exception {
+		Assert.notNull(this.resource, "The resource must not be null.");
+
 		if (!this.resource.exists()) {
 			if (this.strict) {
 				throw new IllegalStateException("Input resource must exist (reader is in 'strict' mode)");

spring-batch-infrastructure/src/main/java/org/springframework/batch/infrastructure/item/json/builder/JsonItemReaderBuilder.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2018-2025 the original author or authors.
+ * Copyright 2018-present 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.
@@ -26,7 +26,6 @@
 import org.springframework.batch.infrastructure.item.support.AbstractItemCountingItemStreamItemReader;
 import org.springframework.batch.infrastructure.item.json.JsonItemReader;
 import org.springframework.batch.infrastructure.item.json.JsonObjectReader;
-import org.springframework.core.io.ByteArrayResource;
 import org.springframework.core.io.Resource;
 import org.springframework.util.Assert;
 import org.springframework.util.StringUtils;
@@ -156,11 +155,10 @@ public JsonItemReader<T> build() {
 		if (this.resource == null) {
 			logger.debug("The resource is null. This is only a valid scenario when "
 					+ "injecting it later as in when using the MultiResourceItemReader");
-			// TODO check if this is feasible
-			this.resource = new ByteArrayResource(new byte[0]);
 		}
-		JsonItemReader<T> reader = new JsonItemReader<>(this.resource, this.jsonObjectReader);
-		reader.setJsonObjectReader(this.jsonObjectReader);
+		JsonItemReader<T> reader = new JsonItemReader<>(this.jsonObjectReader);
+		reader.setResource(this.resource);
+
 		if (this.name != null) {
 			reader.setName(this.name);
 		}