Fix unnecessary reads when chunk size exceeds item count

Resolves #5048

Author: fmbenhassine

spring-batch-core/src/main/java/org/springframework/batch/core/step/item/ChunkOrientedStep.java

@@ -482,6 +482,9 @@ private Chunk<I> readChunk(StepContribution contribution) throws Exception {
 			if (item != null) {
 				chunk.add(item);
 			}
+			else {
+				break;
+			}
 		}
 		return chunk;
 	}

spring-batch-core/src/test/java/org/springframework/batch/core/step/item/ChunkOrientedStepTests.java

@@ -0,0 +1,60 @@
+/*
+ * Copyright 2025-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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.batch.core.step.item;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.batch.core.job.JobExecution;
+import org.springframework.batch.core.job.JobInstance;
+import org.springframework.batch.core.job.parameters.JobParameters;
+import org.springframework.batch.core.repository.JobRepository;
+import org.springframework.batch.core.repository.support.ResourcelessJobRepository;
+import org.springframework.batch.core.step.StepExecution;
+import org.springframework.batch.infrastructure.item.ItemReader;
+import org.springframework.batch.infrastructure.item.ItemWriter;
+
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+/**
+ * @author Mahmoud Ben Hassine
+ */
+public class ChunkOrientedStepTests {
+
+	@Test
+	void testReadNoMoreThanAvailableItems() throws Exception {
+		// given
+		ItemReader<String> reader = mock();
+		ItemWriter<String> writer = chunk -> {
+		};
+		JobRepository jobRepository = new ResourcelessJobRepository();
+		when(reader.read()).thenReturn("1", "2", "3", "4", "5", null);
+		ChunkOrientedStep<String, String> step = new ChunkOrientedStep<>("step", 10, reader, writer, jobRepository);
+		step.afterPropertiesSet();
+		JobInstance jobInstance = new JobInstance(1L, "job");
+		JobExecution jobExecution = new JobExecution(1L, jobInstance, new JobParameters());
+		StepExecution stepExecution = new StepExecution(1L, "step", jobExecution);
+
+		// when
+		step.execute(stepExecution);
+
+		// then
+		verify(reader, times(6)).read();
+	}
+
+}