diff --git a/spring-batch-core/src/main/java/org/springframework/batch/core/repository/dao/MapExecutionContextDao.java b/spring-batch-core/src/main/java/org/springframework/batch/core/repository/dao/MapExecutionContextDao.java
index 9261f8890..c6862023a 100644
--- a/spring-batch-core/src/main/java/org/springframework/batch/core/repository/dao/MapExecutionContextDao.java
+++ b/spring-batch-core/src/main/java/org/springframework/batch/core/repository/dao/MapExecutionContextDao.java
@@ -2,6 +2,7 @@ package org.springframework.batch.core.repository.dao;
 
 import java.util.Map;
 
+import org.apache.commons.lang.SerializationUtils;
 import org.springframework.batch.core.JobExecution;
 import org.springframework.batch.core.StepExecution;
 import org.springframework.batch.item.ExecutionContext;
@@ -17,22 +18,26 @@ public class MapExecutionContextDao implements ExecutionContextDao {
 		contextsByJobExecutionId.clear();
 		contextsByStepExecutionId.clear();
 	}
+	
+	private static ExecutionContext copy(ExecutionContext original) {
+		return (ExecutionContext) SerializationUtils.deserialize(SerializationUtils.serialize(original));
+	}
 
 
 	public ExecutionContext getExecutionContext(StepExecution stepExecution) {
-		return contextsByStepExecutionId.get(stepExecution.getId());
+		return copy(contextsByStepExecutionId.get(stepExecution.getId()));
 	}
 
 	public void persistExecutionContext(StepExecution stepExecution) {
-		contextsByStepExecutionId.put(stepExecution.getId(), stepExecution.getExecutionContext());
+		contextsByStepExecutionId.put(stepExecution.getId(), copy(stepExecution.getExecutionContext()));
 	}
 	
 	public ExecutionContext getExecutionContext(JobExecution jobExecution) {
-		return contextsByJobExecutionId.get(jobExecution.getId());
+		return copy(contextsByJobExecutionId.get(jobExecution.getId()));
 	}
 
 	public void persistExecutionContext(JobExecution jobExecution) {
-		contextsByJobExecutionId.put(jobExecution.getId(), jobExecution.getExecutionContext());
+		contextsByJobExecutionId.put(jobExecution.getId(), copy(jobExecution.getExecutionContext()));
 
 	}
 
diff --git a/spring-batch-core/src/main/java/org/springframework/batch/core/repository/dao/MapStepExecutionDao.java b/spring-batch-core/src/main/java/org/springframework/batch/core/repository/dao/MapStepExecutionDao.java
index 8fba0163b..b9873985b 100644
--- a/spring-batch-core/src/main/java/org/springframework/batch/core/repository/dao/MapStepExecutionDao.java
+++ b/spring-batch-core/src/main/java/org/springframework/batch/core/repository/dao/MapStepExecutionDao.java
@@ -21,6 +21,7 @@ import java.util.Comparator;
 import java.util.List;
 import java.util.Map;
 
+import org.apache.commons.lang.SerializationUtils;
 import org.springframework.batch.core.Entity;
 import org.springframework.batch.core.JobExecution;
 import org.springframework.batch.core.StepExecution;
@@ -40,6 +41,10 @@ public class MapStepExecutionDao implements StepExecutionDao {
 	public static void clear() {
 		executionsByJobExecutionId.clear();
 	}
+	
+	private static StepExecution copy(StepExecution original){
+		return (StepExecution) SerializationUtils.deserialize(SerializationUtils.serialize(original));
+	}
 
 	public void saveStepExecution(StepExecution stepExecution) {
 		Assert.isTrue(stepExecution.getId() == null);
@@ -53,7 +58,7 @@ public class MapStepExecutionDao implements StepExecutionDao {
 		}
 		stepExecution.setId(new Long(currentId++));
 		stepExecution.incrementVersion();
-		executions.put(stepExecution.getStepName(), stepExecution);
+		executions.put(stepExecution.getStepName(), copy(stepExecution));
 	}
 
 	public void updateStepExecution(StepExecution stepExecution) {
@@ -72,7 +77,7 @@ public class MapStepExecutionDao implements StepExecutionDao {
 			}
 
 			stepExecution.incrementVersion();
-			executions.put(stepExecution.getStepName(), stepExecution);
+			executions.put(stepExecution.getStepName(), copy(stepExecution));
 		}
 	}
 
@@ -82,7 +87,7 @@ public class MapStepExecutionDao implements StepExecutionDao {
 			return null;
 		}
 
-		return (StepExecution) executions.get(stepName);
+		return copy(executions.get(stepName));
 	}
 
 	public List<StepExecution> getStepExecutions(JobExecution jobExecution) {
@@ -94,6 +99,11 @@ public class MapStepExecutionDao implements StepExecutionDao {
 				return Long.signum(o2.getId() - o1.getId());
 			}
 		});
-		return result;
+		
+		List<StepExecution> copy = new ArrayList<StepExecution>(result.size());
+		for(StepExecution exec : result) {
+			copy.add(copy(exec));
+		}
+		return copy;
 	}
 }
diff --git a/spring-batch-core/src/test/java/org/springframework/batch/core/job/SimpleJobTests.java b/spring-batch-core/src/test/java/org/springframework/batch/core/job/SimpleJobTests.java
index f662329ac..dc284c278 100644
--- a/spring-batch-core/src/test/java/org/springframework/batch/core/job/SimpleJobTests.java
+++ b/spring-batch-core/src/test/java/org/springframework/batch/core/job/SimpleJobTests.java
@@ -483,6 +483,8 @@ public class SimpleJobTests extends TestCase {
 			}
 			stepExecution.setExitStatus(ExitStatus.FINISHED);
 			stepExecution.setStatus(BatchStatus.COMPLETED);
+			jobRepository.update(stepExecution);
+			jobRepository.updateExecutionContext(stepExecution);
 
 		}
 
diff --git a/spring-batch-core/src/test/java/org/springframework/batch/core/repository/dao/MapJobExecutionDaoTests.java b/spring-batch-core/src/test/java/org/springframework/batch/core/repository/dao/MapJobExecutionDaoTests.java
index 6015ed0ee..a1dba96b0 100644
--- a/spring-batch-core/src/test/java/org/springframework/batch/core/repository/dao/MapJobExecutionDaoTests.java
+++ b/spring-batch-core/src/test/java/org/springframework/batch/core/repository/dao/MapJobExecutionDaoTests.java
@@ -35,6 +35,10 @@ public class MapJobExecutionDaoTests extends AbstractJobExecutionDaoTests {
 		JobExecution retrieved = tested.getJobExecution(jobExecution.getId());
 		assertNull(retrieved.getStartTime());
 		
+		tested.updateJobExecution(jobExecution);
+		jobExecution.setEndTime(new Date());
+		assertNull(retrieved.getEndTime());
+		
 	}
 
 }
diff --git a/spring-batch-core/src/test/java/org/springframework/batch/core/repository/dao/MapStepExecutionDaoTests.java b/spring-batch-core/src/test/java/org/springframework/batch/core/repository/dao/MapStepExecutionDaoTests.java
index ca688f14e..1eaafc483 100644
--- a/spring-batch-core/src/test/java/org/springframework/batch/core/repository/dao/MapStepExecutionDaoTests.java
+++ b/spring-batch-core/src/test/java/org/springframework/batch/core/repository/dao/MapStepExecutionDaoTests.java
@@ -1,7 +1,14 @@
 package org.springframework.batch.core.repository.dao;
 
+import static org.junit.Assert.*;
+
+import java.util.Date;
+
+import org.springframework.batch.core.JobExecution;
+import org.springframework.batch.core.StepExecution;
 import org.springframework.batch.core.repository.JobRepository;
 import org.springframework.batch.core.repository.support.SimpleJobRepository;
+import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.junit.internal.runners.JUnit4ClassRunner;
 
@@ -19,5 +26,29 @@ public class MapStepExecutionDaoTests extends AbstractStepExecutionDaoTests {
 		return new SimpleJobRepository(new MapJobInstanceDao(), new MapJobExecutionDao(), new MapStepExecutionDao(),
 				new MapExecutionContextDao());
 	}
+	
+	/**
+	 * Modifications to saved entity do not affect the persisted object.
+	 */
+	@Test
+	public void testPersistentCopy() {
+		StepExecutionDao tested = new MapStepExecutionDao();
+		JobExecution jobExecution = new JobExecution((long) 77);
+		StepExecution stepExecution = new StepExecution("stepName", jobExecution);
+		
+		assertNull(stepExecution.getEndTime());
+		tested.saveStepExecution(stepExecution);
+		stepExecution.setEndTime(new Date());
+		
+		StepExecution retrieved = tested.getStepExecution(jobExecution, "stepName");
+		assertNull(retrieved.getEndTime());
+		
+		stepExecution.setEndTime(null);
+		tested.updateStepExecution(stepExecution);
+		stepExecution.setEndTime(new Date());
+		
+		StepExecution stored = tested.getStepExecution(jobExecution, "stepName");
+		assertNull(stored.getEndTime());
+	}
 
 }