@Nullable all the way: null-safety at field level

This commits extends nullability declarations to the field level, formalizing the interaction between methods and their underlying fields and therefore avoiding any nullability mismatch.

Issue: SPR-15720

spring-tx/src/main/java/org/springframework/dao/support/PersistenceExceptionTranslationInterceptor.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2013 the original author or authors.
+ * Copyright 2002-2017 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.
@@ -27,6 +27,7 @@ import org.springframework.beans.factory.BeanFactoryAware;
 import org.springframework.beans.factory.BeanFactoryUtils;
 import org.springframework.beans.factory.InitializingBean;
 import org.springframework.beans.factory.ListableBeanFactory;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.ReflectionUtils;
 
@@ -47,10 +48,12 @@ import org.springframework.util.ReflectionUtils;
 public class PersistenceExceptionTranslationInterceptor
 		implements MethodInterceptor, BeanFactoryAware, InitializingBean {
 
+	@Nullable
 	private volatile PersistenceExceptionTranslator persistenceExceptionTranslator;
 
 	private boolean alwaysTranslate = false;
 
+	@Nullable
 	private ListableBeanFactory beanFactory;
 
 
@@ -141,10 +144,13 @@ public class PersistenceExceptionTranslationInterceptor
 				throw ex;
 			}
 			else {
-				if (this.persistenceExceptionTranslator == null) {
-					this.persistenceExceptionTranslator = detectPersistenceExceptionTranslators(this.beanFactory);
+				PersistenceExceptionTranslator translator = this.persistenceExceptionTranslator;
+				if (translator == null) {
+					Assert.state(this.beanFactory != null, "No PersistenceExceptionTranslator set");
+					translator = detectPersistenceExceptionTranslators(this.beanFactory);
+					this.persistenceExceptionTranslator = translator;
 				}
-				throw DataAccessUtils.translateIfNecessary(ex, this.persistenceExceptionTranslator);
+				throw DataAccessUtils.translateIfNecessary(ex, translator);
 			}
 		}
 	}

spring-tx/src/main/java/org/springframework/jca/cci/connection/CciLocalTransactionManager.java

@@ -66,6 +66,7 @@ import org.springframework.util.Assert;
 public class CciLocalTransactionManager extends AbstractPlatformTransactionManager
 		implements ResourceTransactionManager, InitializingBean {
 
+	@Nullable
 	private ConnectionFactory connectionFactory;
 
 
@@ -273,6 +274,7 @@ public class CciLocalTransactionManager extends AbstractPlatformTransactionManag
 	 */
 	private static class CciLocalTransactionObject {
 
+		@Nullable
 		private ConnectionHolder connectionHolder;
 
 		public void setConnectionHolder(@Nullable ConnectionHolder connectionHolder) {

spring-tx/src/main/java/org/springframework/jca/cci/connection/SingleConnectionFactory.java

@@ -57,9 +57,11 @@ public class SingleConnectionFactory extends DelegatingConnectionFactory impleme
 	protected final Log logger = LogFactory.getLog(getClass());
 
 	/** Wrapped Connection */
+	@Nullable
 	private Connection target;
 
 	/** Proxy Connection */
+	@Nullable
 	private Connection connection;
 
 	/** Synchronization monitor for the shared Connection */

spring-tx/src/main/java/org/springframework/jca/cci/core/CciTemplate.java

@@ -72,10 +72,13 @@ public class CciTemplate implements CciOperations {
 
 	private final Log logger = LogFactory.getLog(getClass());
 
+	@Nullable
 	private ConnectionFactory connectionFactory;
 
+	@Nullable
 	private ConnectionSpec connectionSpec;
 
+	@Nullable
 	private RecordCreator outputRecordCreator;
 
 
@@ -106,7 +109,9 @@ public class CciTemplate implements CciOperations {
 	 */
 	public CciTemplate(ConnectionFactory connectionFactory, @Nullable ConnectionSpec connectionSpec) {
 		setConnectionFactory(connectionFactory);
-		setConnectionSpec(connectionSpec);
+		if (connectionSpec != null) {
+			setConnectionSpec(connectionSpec);
+		}
 		afterPropertiesSet();
 	}
 
@@ -114,7 +119,7 @@ public class CciTemplate implements CciOperations {
 	/**
 	 * Set the CCI ConnectionFactory to obtain Connections from.
 	 */
-	public void setConnectionFactory(@Nullable ConnectionFactory connectionFactory) {
+	public void setConnectionFactory(ConnectionFactory connectionFactory) {
 		this.connectionFactory = connectionFactory;
 	}
 
@@ -136,7 +141,7 @@ public class CciTemplate implements CciOperations {
 	 * Set the CCI ConnectionSpec that this template instance is
 	 * supposed to obtain Connections for.
 	 */
-	public void setConnectionSpec(@Nullable ConnectionSpec connectionSpec) {
+	public void setConnectionSpec(ConnectionSpec connectionSpec) {
 		this.connectionSpec = connectionSpec;
 	}
 
@@ -160,7 +165,7 @@ public class CciTemplate implements CciOperations {
 	 * @see javax.resource.cci.Interaction#execute(javax.resource.cci.InteractionSpec, Record)
 	 * @see javax.resource.cci.Interaction#execute(javax.resource.cci.InteractionSpec, Record, Record)
 	 */
-	public void setOutputRecordCreator(@Nullable RecordCreator creator) {
+	public void setOutputRecordCreator(RecordCreator creator) {
 		this.outputRecordCreator = creator;
 	}
 
@@ -189,10 +194,11 @@ public class CciTemplate implements CciOperations {
 	 * @see #setConnectionSpec
 	 */
 	public CciTemplate getDerivedTemplate(ConnectionSpec connectionSpec) {
-		CciTemplate derived = new CciTemplate();
-		derived.setConnectionFactory(getConnectionFactory());
-		derived.setConnectionSpec(connectionSpec);
-		derived.setOutputRecordCreator(getOutputRecordCreator());
+		CciTemplate derived = new CciTemplate(obtainConnectionFactory(), connectionSpec);
+		RecordCreator recordCreator = getOutputRecordCreator();
+		if (recordCreator != null) {
+			derived.setOutputRecordCreator(recordCreator);
+		}
 		return derived;
 	}
 

spring-tx/src/main/java/org/springframework/jca/cci/core/support/CciDaoSupport.java

@@ -47,6 +47,7 @@ import org.springframework.util.Assert;
  */
 public abstract class CciDaoSupport extends DaoSupport {
 
+	@Nullable
 	private CciTemplate cciTemplate;
 
 
@@ -77,7 +78,7 @@ public abstract class CciDaoSupport extends DaoSupport {
 	 */
 	@Nullable
 	public final ConnectionFactory getConnectionFactory() {
-		return this.cciTemplate.getConnectionFactory();
+		return (this.cciTemplate != null ? this.cciTemplate.getConnectionFactory() : null);
 	}
 
 	/**
@@ -92,6 +93,7 @@ public abstract class CciDaoSupport extends DaoSupport {
 	 * Return the CciTemplate for this DAO,
 	 * pre-initialized with the ConnectionFactory or set explicitly.
 	 */
+	@Nullable
 	public final CciTemplate getCciTemplate() {
 	  return this.cciTemplate;
 	}
@@ -114,7 +116,9 @@ public abstract class CciDaoSupport extends DaoSupport {
 	 * @see org.springframework.jca.cci.core.CciTemplate#getDerivedTemplate(javax.resource.cci.ConnectionSpec)
 	 */
 	protected final CciTemplate getCciTemplate(ConnectionSpec connectionSpec) {
-		return getCciTemplate().getDerivedTemplate(connectionSpec);
+		CciTemplate cciTemplate = getCciTemplate();
+		Assert.state(cciTemplate != null, "No CciTemplate set");
+		return cciTemplate.getDerivedTemplate(connectionSpec);
 	}
 
 	/**

spring-tx/src/main/java/org/springframework/jca/cci/object/EisOperation.java

@@ -21,6 +21,7 @@ import javax.resource.cci.InteractionSpec;
 
 import org.springframework.beans.factory.InitializingBean;
 import org.springframework.jca.cci.core.CciTemplate;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
 /**
@@ -39,6 +40,7 @@ public abstract class EisOperation implements InitializingBean {
 
 	private CciTemplate cciTemplate = new CciTemplate();
 
+	@Nullable
 	private InteractionSpec interactionSpec;
 
 
@@ -76,6 +78,7 @@ public abstract class EisOperation implements InitializingBean {
 	/**
 	 * Return the CCI InteractionSpec for this operation.
 	 */
+	@Nullable
 	public InteractionSpec getInteractionSpec() {
 		return this.interactionSpec;
 	}
@@ -86,7 +89,7 @@ public abstract class EisOperation implements InitializingBean {
 		this.cciTemplate.afterPropertiesSet();
 
 		if (this.interactionSpec == null) {
-			throw new IllegalArgumentException("interactionSpec is required");
+			throw new IllegalArgumentException("InteractionSpec is required");
 		}
 	}
 

spring-tx/src/main/java/org/springframework/jca/cci/object/MappingRecordOperation.java

@@ -27,6 +27,7 @@ import org.springframework.dao.DataAccessException;
 import org.springframework.jca.cci.core.RecordCreator;
 import org.springframework.jca.cci.core.RecordExtractor;
 import org.springframework.lang.Nullable;
+import org.springframework.util.Assert;
 
 /**
  * EIS operation object that expects mapped input and output objects,
@@ -88,8 +89,10 @@ public abstract class MappingRecordOperation extends EisOperation {
 	 */
 	@Nullable
 	public Object execute(Object inputObject) throws DataAccessException {
+		InteractionSpec interactionSpec = getInteractionSpec();
+		Assert.state(interactionSpec != null, "No InteractionSpec set");
 		return getCciTemplate().execute(
-				getInteractionSpec(), new RecordCreatorImpl(inputObject), new RecordExtractorImpl());
+				interactionSpec, new RecordCreatorImpl(inputObject), new RecordExtractorImpl());
 	}
 
 

spring-tx/src/main/java/org/springframework/jca/cci/object/SimpleRecordOperation.java

@@ -22,6 +22,7 @@ import javax.resource.cci.Record;
 
 import org.springframework.dao.DataAccessException;
 import org.springframework.lang.Nullable;
+import org.springframework.util.Assert;
 
 /**
  * EIS operation object that accepts a passed-in CCI input Record
@@ -48,6 +49,7 @@ public class SimpleRecordOperation extends EisOperation {
 		setInteractionSpec(interactionSpec);
 	}
 
+
 	/**
 	 * Execute the CCI interaction encapsulated by this operation object.
 	 * <p>This method will call CCI's {@code Interaction.execute} variant
@@ -59,7 +61,9 @@ public class SimpleRecordOperation extends EisOperation {
 	 */
 	@Nullable
 	public Record execute(Record inputRecord) throws DataAccessException {
-		return getCciTemplate().execute(getInteractionSpec(), inputRecord);
+		InteractionSpec interactionSpec = getInteractionSpec();
+		Assert.state(interactionSpec != null, "No InteractionSpec set");
+		return getCciTemplate().execute(interactionSpec, inputRecord);
 	}
 
 	/**
@@ -72,7 +76,9 @@ public class SimpleRecordOperation extends EisOperation {
 	 * @see javax.resource.cci.Interaction#execute(javax.resource.cci.InteractionSpec, Record, Record)
 	 */
 	public void execute(Record inputRecord, Record outputRecord) throws DataAccessException {
-		getCciTemplate().execute(getInteractionSpec(), inputRecord, outputRecord);
+		InteractionSpec interactionSpec = getInteractionSpec();
+		Assert.state(interactionSpec != null, "No InteractionSpec set");
+		getCciTemplate().execute(interactionSpec, inputRecord, outputRecord);
 	}
 
 }

spring-tx/src/main/java/org/springframework/jca/context/BootstrapContextAwareProcessor.java

@@ -36,6 +36,7 @@ import org.springframework.lang.Nullable;
  */
 class BootstrapContextAwareProcessor implements BeanPostProcessor {
 
+	@Nullable
 	private final BootstrapContext bootstrapContext;
 
 

spring-tx/src/main/java/org/springframework/jca/endpoint/AbstractMessageEndpointFactory.java

@@ -33,6 +33,7 @@ import org.springframework.beans.factory.BeanNameAware;
 import org.springframework.lang.Nullable;
 import org.springframework.transaction.jta.SimpleTransactionFactory;
 import org.springframework.transaction.jta.TransactionFactory;
+import org.springframework.util.Assert;
 
 /**
  * Abstract base implementation of the JCA 1.7
@@ -49,12 +50,15 @@ public abstract class AbstractMessageEndpointFactory implements MessageEndpointF
 	/** Logger available to subclasses */
 	protected final Log logger = LogFactory.getLog(getClass());
 
+	@Nullable
 	private TransactionFactory transactionFactory;
 
+	@Nullable
 	private String transactionName;
 
 	private int transactionTimeout = -1;
 
+	@Nullable
 	private String beanName;
 
 
@@ -201,10 +205,12 @@ public abstract class AbstractMessageEndpointFactory implements MessageEndpointF
 	 */
 	protected abstract class AbstractMessageEndpoint implements MessageEndpoint {
 
+		@Nullable
 		private TransactionDelegate transactionDelegate;
 
 		private boolean beforeDeliveryCalled = false;
 
+		@Nullable
 		private ClassLoader previousContextClassLoader;
 
 		/**
@@ -228,6 +234,7 @@ public abstract class AbstractMessageEndpointFactory implements MessageEndpointF
 		@Override
 		public void beforeDelivery(@Nullable Method method) throws ResourceException {
 			this.beforeDeliveryCalled = true;
+			Assert.state(this.transactionDelegate != null, "Not initialized");
 			try {
 				this.transactionDelegate.beginTransaction();
 			}
@@ -263,6 +270,7 @@ public abstract class AbstractMessageEndpointFactory implements MessageEndpointF
 		 * @param ex the exception thrown from the concrete endpoint
 		 */
 		protected final void onEndpointException(Throwable ex) {
+			Assert.state(this.transactionDelegate != null, "Not initialized");
 			this.transactionDelegate.setRollbackOnly();
 		}
 
@@ -275,6 +283,7 @@ public abstract class AbstractMessageEndpointFactory implements MessageEndpointF
 		 */
 		@Override
 		public void afterDelivery() throws ResourceException {
+			Assert.state(this.transactionDelegate != null, "Not initialized");
 			this.beforeDeliveryCalled = false;
 			Thread.currentThread().setContextClassLoader(this.previousContextClassLoader);
 			this.previousContextClassLoader = null;
@@ -288,12 +297,14 @@ public abstract class AbstractMessageEndpointFactory implements MessageEndpointF
 
 		@Override
 		public void release() {
-			try {
-				this.transactionDelegate.setRollbackOnly();
-				this.transactionDelegate.endTransaction();
-			}
-			catch (Throwable ex) {
-				logger.error("Could not complete unfinished transaction on endpoint release", ex);
+			if (this.transactionDelegate != null) {
+				try {
+					this.transactionDelegate.setRollbackOnly();
+					this.transactionDelegate.endTransaction();
+				}
+				catch (Throwable ex) {
+					logger.error("Could not complete unfinished transaction on endpoint release", ex);
+				}
 			}
 		}
 	}
@@ -305,8 +316,10 @@ public abstract class AbstractMessageEndpointFactory implements MessageEndpointF
 	 */
 	private class TransactionDelegate {
 
+		@Nullable
 		private final XAResource xaResource;
 
+		@Nullable
 		private Transaction transaction;
 
 		private boolean rollbackOnly;

spring-tx/src/main/java/org/springframework/jca/support/LocalConnectionFactoryBean.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2017 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.
@@ -22,6 +22,7 @@ import javax.resource.spi.ManagedConnectionFactory;
 
 import org.springframework.beans.factory.FactoryBean;
 import org.springframework.beans.factory.InitializingBean;
+import org.springframework.lang.Nullable;
 
 /**
  * {@link org.springframework.beans.factory.FactoryBean} that creates
@@ -70,10 +71,13 @@ import org.springframework.beans.factory.InitializingBean;
  */
 public class LocalConnectionFactoryBean implements FactoryBean<Object>, InitializingBean {
 
+	@Nullable
 	private ManagedConnectionFactory managedConnectionFactory;
 
+	@Nullable
 	private ConnectionManager connectionManager;
 
+	@Nullable
 	private Object connectionFactory;
 
 

spring-tx/src/main/java/org/springframework/jca/support/ResourceAdapterFactoryBean.java

@@ -26,6 +26,7 @@ import org.springframework.beans.BeanUtils;
 import org.springframework.beans.factory.DisposableBean;
 import org.springframework.beans.factory.FactoryBean;
 import org.springframework.beans.factory.InitializingBean;
+import org.springframework.lang.Nullable;
 
 /**
  * {@link org.springframework.beans.factory.FactoryBean} that bootstraps
@@ -49,12 +50,16 @@ import org.springframework.beans.factory.InitializingBean;
  */
 public class ResourceAdapterFactoryBean implements FactoryBean<ResourceAdapter>, InitializingBean, DisposableBean {
 
+	@Nullable
 	private ResourceAdapter resourceAdapter;
 
+	@Nullable
 	private BootstrapContext bootstrapContext;
 
+	@Nullable
 	private WorkManager workManager;
 
+	@Nullable
 	private XATerminator xaTerminator;
 
 
@@ -145,7 +150,9 @@ public class ResourceAdapterFactoryBean implements FactoryBean<ResourceAdapter>,
 	 */
 	@Override
 	public void destroy() {
-		this.resourceAdapter.stop();
+		if (this.resourceAdapter != null) {
+			this.resourceAdapter.stop();
+		}
 	}
 
 }

spring-tx/src/main/java/org/springframework/jca/support/SimpleBootstrapContext.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2017 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.
@@ -17,7 +17,6 @@
 package org.springframework.jca.support;
 
 import java.util.Timer;
-
 import javax.resource.spi.BootstrapContext;
 import javax.resource.spi.UnavailableException;
 import javax.resource.spi.XATerminator;
@@ -26,6 +25,7 @@ import javax.resource.spi.work.WorkManager;
 import javax.transaction.TransactionSynchronizationRegistry;
 
 import org.springframework.lang.Nullable;
+import org.springframework.util.Assert;
 
 /**
  * Simple implementation of the JCA 1.7 {@link javax.resource.spi.BootstrapContext}
@@ -41,10 +41,13 @@ import org.springframework.lang.Nullable;
  */
 public class SimpleBootstrapContext implements BootstrapContext {
 
+	@Nullable
 	private WorkManager workManager;
 
+	@Nullable
 	private XATerminator xaTerminator;
 
+	@Nullable
 	private TransactionSynchronizationRegistry transactionSynchronizationRegistry;
 
 
@@ -87,13 +90,12 @@ public class SimpleBootstrapContext implements BootstrapContext {
 
 	@Override
 	public WorkManager getWorkManager() {
-		if (this.workManager == null) {
-			throw new IllegalStateException("No WorkManager available");
-		}
+		Assert.state(this.workManager != null, "No WorkManager available");
 		return this.workManager;
 	}
 
 	@Override
+	@Nullable
 	public XATerminator getXATerminator() {
 		return this.xaTerminator;
 	}
@@ -109,6 +111,7 @@ public class SimpleBootstrapContext implements BootstrapContext {
 	}
 
 	@Override
+	@Nullable
 	public TransactionSynchronizationRegistry getTransactionSynchronizationRegistry() {
 		return this.transactionSynchronizationRegistry;
 	}

spring-tx/src/main/java/org/springframework/jca/work/SimpleTaskWorkManager.java

@@ -63,8 +63,10 @@ import org.springframework.util.Assert;
  */
 public class SimpleTaskWorkManager implements WorkManager {
 
+	@Nullable
 	private TaskExecutor syncTaskExecutor = new SyncTaskExecutor();
 
+	@Nullable
 	private AsyncTaskExecutor asyncTaskExecutor = new SimpleAsyncTaskExecutor();
 
 
@@ -238,16 +240,11 @@ public class SimpleTaskWorkManager implements WorkManager {
 			try {
 				this.work.run();
 			}
-			catch (RuntimeException ex) {
+			catch (RuntimeException | Error ex) {
 				this.workListener.workCompleted(
 						new WorkEvent(this, WorkEvent.WORK_COMPLETED, this.work, new WorkCompletedException(ex)));
 				throw ex;
 			}
-			catch (Error err) {
-				this.workListener.workCompleted(
-						new WorkEvent(this, WorkEvent.WORK_COMPLETED, this.work, new WorkCompletedException(err)));
-				throw err;
-			}
 			this.workListener.workCompleted(new WorkEvent(this, WorkEvent.WORK_COMPLETED, this.work, null));
 		}
 

spring-tx/src/main/java/org/springframework/jca/work/WorkManagerTaskExecutor.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2017 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.
@@ -70,16 +70,20 @@ import org.springframework.util.concurrent.ListenableFutureTask;
 public class WorkManagerTaskExecutor extends JndiLocatorSupport
 		implements AsyncListenableTaskExecutor, SchedulingTaskExecutor, WorkManager, BootstrapContextAware, InitializingBean {
 
+	@Nullable
 	private WorkManager workManager;
 
+	@Nullable
 	private String workManagerName;
 
 	private boolean blockUntilStarted = false;
 
 	private boolean blockUntilCompleted = false;
 
+	@Nullable
 	private WorkListener workListener;
 
+	@Nullable
 	private TaskDecorator taskDecorator;
 
 
@@ -198,6 +202,11 @@ public class WorkManagerTaskExecutor extends JndiLocatorSupport
 		return new SimpleTaskWorkManager();
 	}
 
+	private WorkManager obtainWorkManager() {
+		Assert.state(this.workManager != null, "No WorkManager specified");
+		return this.workManager;
+	}
+
 
 	//-------------------------------------------------------------------------
 	// Implementation of the Spring SchedulingTaskExecutor interface
@@ -210,31 +219,30 @@ public class WorkManagerTaskExecutor extends JndiLocatorSupport
 
 	@Override
 	public void execute(Runnable task, long startTimeout) {
-		Assert.state(this.workManager != null, "No WorkManager specified");
 		Work work = new DelegatingWork(this.taskDecorator != null ? this.taskDecorator.decorate(task) : task);
 		try {
 			if (this.blockUntilCompleted) {
 				if (startTimeout != TIMEOUT_INDEFINITE || this.workListener != null) {
-					this.workManager.doWork(work, startTimeout, null, this.workListener);
+					obtainWorkManager().doWork(work, startTimeout, null, this.workListener);
 				}
 				else {
-					this.workManager.doWork(work);
+					obtainWorkManager().doWork(work);
 				}
 			}
 			else if (this.blockUntilStarted) {
 				if (startTimeout != TIMEOUT_INDEFINITE || this.workListener != null) {
-					this.workManager.startWork(work, startTimeout, null, this.workListener);
+					obtainWorkManager().startWork(work, startTimeout, null, this.workListener);
 				}
 				else {
-					this.workManager.startWork(work);
+					obtainWorkManager().startWork(work);
 				}
 			}
 			else {
 				if (startTimeout != TIMEOUT_INDEFINITE || this.workListener != null) {
-					this.workManager.scheduleWork(work, startTimeout, null, this.workListener);
+					obtainWorkManager().scheduleWork(work, startTimeout, null, this.workListener);
 				}
 				else {
-					this.workManager.scheduleWork(work);
+					obtainWorkManager().scheduleWork(work);
 				}
 			}
 		}
@@ -294,38 +302,38 @@ public class WorkManagerTaskExecutor extends JndiLocatorSupport
 
 	@Override
 	public void doWork(Work work) throws WorkException {
-		this.workManager.doWork(work);
+		obtainWorkManager().doWork(work);
 	}
 
 	@Override
 	public void doWork(Work work, long delay, ExecutionContext executionContext, WorkListener workListener)
 			throws WorkException {
 
-		this.workManager.doWork(work, delay, executionContext, workListener);
+		obtainWorkManager().doWork(work, delay, executionContext, workListener);
 	}
 
 	@Override
 	public long startWork(Work work) throws WorkException {
-		return this.workManager.startWork(work);
+		return obtainWorkManager().startWork(work);
 	}
 
 	@Override
 	public long startWork(Work work, long delay, ExecutionContext executionContext, WorkListener workListener)
 			throws WorkException {
 
-		return this.workManager.startWork(work, delay, executionContext, workListener);
+		return obtainWorkManager().startWork(work, delay, executionContext, workListener);
 	}
 
 	@Override
 	public void scheduleWork(Work work) throws WorkException {
-		this.workManager.scheduleWork(work);
+		obtainWorkManager().scheduleWork(work);
 	}
 
 	@Override
 	public void scheduleWork(Work work, long delay, ExecutionContext executionContext, WorkListener workListener)
 			throws WorkException {
 
-		this.workManager.scheduleWork(work, delay, executionContext, workListener);
+		obtainWorkManager().scheduleWork(work, delay, executionContext, workListener);
 	}
 
 }

spring-tx/src/main/java/org/springframework/transaction/TransactionSystemException.java

@@ -29,6 +29,7 @@ import org.springframework.util.Assert;
 @SuppressWarnings("serial")
 public class TransactionSystemException extends TransactionException {
 
+	@Nullable
 	private Throwable applicationException;
 
 

spring-tx/src/main/java/org/springframework/transaction/annotation/AbstractTransactionManagementConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2017 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.
@@ -26,6 +26,7 @@ import org.springframework.context.annotation.ImportAware;
 import org.springframework.context.annotation.Role;
 import org.springframework.core.annotation.AnnotationAttributes;
 import org.springframework.core.type.AnnotationMetadata;
+import org.springframework.lang.Nullable;
 import org.springframework.transaction.PlatformTransactionManager;
 import org.springframework.transaction.config.TransactionManagementConfigUtils;
 import org.springframework.transaction.event.TransactionalEventListenerFactory;
@@ -43,11 +44,13 @@ import org.springframework.util.CollectionUtils;
 @Configuration
 public abstract class AbstractTransactionManagementConfiguration implements ImportAware {
 
+	@Nullable
 	protected AnnotationAttributes enableTx;
 
 	/**
 	 * Default transaction manager, as configured through a {@link TransactionManagementConfigurer}.
 	 */
+	@Nullable
 	protected PlatformTransactionManager txManager;
 
 

spring-tx/src/main/java/org/springframework/transaction/annotation/ProxyTransactionManagementConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2017 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.
@@ -43,7 +43,9 @@ public class ProxyTransactionManagementConfiguration extends AbstractTransaction
 		BeanFactoryTransactionAttributeSourceAdvisor advisor = new BeanFactoryTransactionAttributeSourceAdvisor();
 		advisor.setTransactionAttributeSource(transactionAttributeSource());
 		advisor.setAdvice(transactionInterceptor());
-		advisor.setOrder(this.enableTx.<Integer>getNumber("order"));
+		if (this.enableTx != null) {
+			advisor.setOrder(this.enableTx.<Integer>getNumber("order"));
+		}
 		return advisor;
 	}
 

spring-tx/src/main/java/org/springframework/transaction/config/JtaTransactionManagerFactoryBean.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2017 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.
@@ -18,6 +18,7 @@ package org.springframework.transaction.config;
 
 import org.springframework.beans.BeanUtils;
 import org.springframework.beans.factory.FactoryBean;
+import org.springframework.lang.Nullable;
 import org.springframework.transaction.jta.JtaTransactionManager;
 import org.springframework.util.ClassUtils;
 
@@ -50,6 +51,7 @@ public class JtaTransactionManagerFactoryBean implements FactoryBean<JtaTransact
 			"com.ibm.wsspi.uow.UOWManager", JtaTransactionManagerFactoryBean.class.getClassLoader());
 
 
+	@Nullable
 	private final JtaTransactionManager transactionManager;
 
 

spring-tx/src/main/java/org/springframework/transaction/event/ApplicationListenerMethodTransactionalAdapter.java

@@ -50,10 +50,11 @@ class ApplicationListenerMethodTransactionalAdapter extends ApplicationListenerM
 
 	public ApplicationListenerMethodTransactionalAdapter(String beanName, Class<?> targetClass, Method method) {
 		super(beanName, targetClass, method);
-		this.annotation = AnnotatedElementUtils.findMergedAnnotation(method, TransactionalEventListener.class);
-		if (this.annotation == null) {
+		TransactionalEventListener ann = AnnotatedElementUtils.findMergedAnnotation(method, TransactionalEventListener.class);
+		if (ann == null) {
 			throw new IllegalStateException("No TransactionalEventListener annotation found on method: " + method);
 		}
+		this.annotation = ann;
 	}
 
 

spring-tx/src/main/java/org/springframework/transaction/interceptor/DefaultTransactionAttribute.java

@@ -30,8 +30,10 @@ import org.springframework.transaction.support.DefaultTransactionDefinition;
 @SuppressWarnings("serial")
 public class DefaultTransactionAttribute extends DefaultTransactionDefinition implements TransactionAttribute {
 
+	@Nullable
 	private String qualifier;
 
+	@Nullable
 	private String descriptor;
 
 

spring-tx/src/main/java/org/springframework/transaction/interceptor/MethodMapTransactionAttributeSource.java

@@ -50,8 +50,10 @@ public class MethodMapTransactionAttributeSource
 	protected final Log logger = LogFactory.getLog(getClass());
 
 	/** Map from method name to attribute value */
+	@Nullable
 	private Map<String, TransactionAttribute> methodMap;
 
+	@Nullable
 	private ClassLoader beanClassLoader = ClassUtils.getDefaultClassLoader();
 
 	private boolean eagerlyInitialized = false;

spring-tx/src/main/java/org/springframework/transaction/interceptor/RuleBasedTransactionAttribute.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2017 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.
@@ -24,6 +24,8 @@ import java.util.List;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
+import org.springframework.lang.Nullable;
+
 /**
  * TransactionAttribute implementation that works out whether a given exception
  * should cause transaction rollback by applying a number of rollback rules,
@@ -50,6 +52,7 @@ public class RuleBasedTransactionAttribute extends DefaultTransactionAttribute i
 	/** Static for optimal serializability */
 	private static final Log logger = LogFactory.getLog(RuleBasedTransactionAttribute.class);
 
+	@Nullable
 	private List<RollbackRuleAttribute> rollbackRules;
 
 
@@ -78,7 +81,7 @@ public class RuleBasedTransactionAttribute extends DefaultTransactionAttribute i
 	 */
 	public RuleBasedTransactionAttribute(RuleBasedTransactionAttribute other) {
 		super(other);
-		this.rollbackRules = new ArrayList<>(other.rollbackRules);
+		this.rollbackRules = (other.rollbackRules != null ? new ArrayList<>(other.rollbackRules) : null);
 	}
 
 	/**

spring-tx/src/main/java/org/springframework/transaction/interceptor/TransactionAspectSupport.java

@@ -129,12 +129,16 @@ public abstract class TransactionAspectSupport implements BeanFactoryAware, Init
 
 	protected final Log logger = LogFactory.getLog(getClass());
 
+	@Nullable
 	private String transactionManagerBeanName;
 
+	@Nullable
 	private PlatformTransactionManager transactionManager;
 
+	@Nullable
 	private TransactionAttributeSource transactionAttributeSource;
 
+	@Nullable
 	private BeanFactory beanFactory;
 
 	private final ConcurrentMap<Object, PlatformTransactionManager> transactionManagerCache =
@@ -151,6 +155,7 @@ public abstract class TransactionAspectSupport implements BeanFactoryAware, Init
 	/**
 	 * Return the name of the default transaction manager bean.
 	 */
+	@Nullable
 	protected final String getTransactionManagerBeanName() {
 		return this.transactionManagerBeanName;
 	}
@@ -236,6 +241,7 @@ public abstract class TransactionAspectSupport implements BeanFactoryAware, Init
 	/**
 	 * Return the BeanFactory to use for retrieving PlatformTransactionManager beans.
 	 */
+	@Nullable
 	protected final BeanFactory getBeanFactory() {
 		return this.beanFactory;
 	}
@@ -361,10 +367,10 @@ public abstract class TransactionAspectSupport implements BeanFactoryAware, Init
 
 		String qualifier = txAttr.getQualifier();
 		if (StringUtils.hasText(qualifier)) {
-			return determineQualifiedTransactionManager(qualifier);
+			return determineQualifiedTransactionManager(this.beanFactory, qualifier);
 		}
 		else if (StringUtils.hasText(this.transactionManagerBeanName)) {
-			return determineQualifiedTransactionManager(this.transactionManagerBeanName);
+			return determineQualifiedTransactionManager(this.beanFactory, this.transactionManagerBeanName);
 		}
 		else {
 			PlatformTransactionManager defaultTransactionManager = getTransactionManager();
@@ -380,11 +386,11 @@ public abstract class TransactionAspectSupport implements BeanFactoryAware, Init
 		}
 	}
 
-	private PlatformTransactionManager determineQualifiedTransactionManager(String qualifier) {
+	private PlatformTransactionManager determineQualifiedTransactionManager(BeanFactory beanFactory, String qualifier) {
 		PlatformTransactionManager txManager = this.transactionManagerCache.get(qualifier);
 		if (txManager == null) {
 			txManager = BeanFactoryAnnotationUtils.qualifiedBeanOfType(
-					this.beanFactory, PlatformTransactionManager.class, qualifier);
+					beanFactory, PlatformTransactionManager.class, qualifier);
 			this.transactionManagerCache.putIfAbsent(qualifier, txManager);
 		}
 		return txManager;
@@ -505,7 +511,7 @@ public abstract class TransactionAspectSupport implements BeanFactoryAware, Init
 	 * @param txInfo information about the current transaction
 	 */
 	protected void commitTransactionAfterReturning(@Nullable TransactionInfo txInfo) {
-		if (txInfo != null && txInfo.hasTransaction()) {
+		if (txInfo != null && txInfo.getTransactionStatus() != null) {
 			if (logger.isTraceEnabled()) {
 				logger.trace("Completing transaction for [" + txInfo.getJoinpointIdentification() + "]");
 			}
@@ -520,7 +526,7 @@ public abstract class TransactionAspectSupport implements BeanFactoryAware, Init
 	 * @param ex throwable encountered
 	 */
 	protected void completeTransactionAfterThrowing(@Nullable TransactionInfo txInfo, Throwable ex) {
-		if (txInfo != null && txInfo.hasTransaction()) {
+		if (txInfo != null && txInfo.getTransactionStatus() != null) {
 			if (logger.isTraceEnabled()) {
 				logger.trace("Completing transaction for [" + txInfo.getJoinpointIdentification() +
 						"] after exception: " + ex);
@@ -584,14 +590,18 @@ public abstract class TransactionAspectSupport implements BeanFactoryAware, Init
 	 */
 	protected final class TransactionInfo {
 
+		@Nullable
 		private final PlatformTransactionManager transactionManager;
 
+		@Nullable
 		private final TransactionAttribute transactionAttribute;
 
 		private final String joinpointIdentification;
 
+		@Nullable
 		private TransactionStatus transactionStatus;
 
+		@Nullable
 		private TransactionInfo oldTransactionInfo;
 
 		public TransactionInfo(@Nullable PlatformTransactionManager transactionManager,
@@ -624,6 +634,7 @@ public abstract class TransactionAspectSupport implements BeanFactoryAware, Init
 			this.transactionStatus = status;
 		}
 
+		@Nullable
 		public TransactionStatus getTransactionStatus() {
 			return this.transactionStatus;
 		}

spring-tx/src/main/java/org/springframework/transaction/interceptor/TransactionAttribute.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2017 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.
@@ -16,6 +16,7 @@
 
 package org.springframework.transaction.interceptor;
 
+import org.springframework.lang.Nullable;
 import org.springframework.transaction.TransactionDefinition;
 
 /**
@@ -36,6 +37,7 @@ public interface TransactionAttribute extends TransactionDefinition {
 	 * <p>This may be used for choosing a corresponding transaction manager
 	 * to process this specific transaction.
 	 */
+	@Nullable
 	String getQualifier();
 
 	/**

spring-tx/src/main/java/org/springframework/transaction/interceptor/TransactionAttributeSourceAdvisor.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2017 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.
@@ -21,6 +21,8 @@ import org.aopalliance.aop.Advice;
 import org.springframework.aop.ClassFilter;
 import org.springframework.aop.Pointcut;
 import org.springframework.aop.support.AbstractPointcutAdvisor;
+import org.springframework.lang.Nullable;
+import org.springframework.util.Assert;
 
 /**
  * Advisor driven by a {@link TransactionAttributeSource}, used to include
@@ -38,6 +40,7 @@ import org.springframework.aop.support.AbstractPointcutAdvisor;
 @SuppressWarnings("serial")
 public class TransactionAttributeSourceAdvisor extends AbstractPointcutAdvisor {
 
+	@Nullable
 	private TransactionInterceptor transactionInterceptor;
 
 	private final TransactionAttributeSourcePointcut pointcut = new TransactionAttributeSourcePointcut() {
@@ -81,6 +84,7 @@ public class TransactionAttributeSourceAdvisor extends AbstractPointcutAdvisor {
 
 	@Override
 	public Advice getAdvice() {
+		Assert.state(this.transactionInterceptor != null, "No TransactionInterceptor set");
 		return this.transactionInterceptor;
 	}
 

spring-tx/src/main/java/org/springframework/transaction/interceptor/TransactionProxyFactoryBean.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2017 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.
@@ -26,6 +26,7 @@ import org.springframework.beans.factory.BeanFactory;
 import org.springframework.beans.factory.BeanFactoryAware;
 import org.springframework.beans.factory.FactoryBean;
 import org.springframework.beans.factory.ListableBeanFactory;
+import org.springframework.lang.Nullable;
 import org.springframework.transaction.PlatformTransactionManager;
 
 /**
@@ -117,6 +118,7 @@ public class TransactionProxyFactoryBean extends AbstractSingletonProxyFactoryBe
 
 	private final TransactionInterceptor transactionInterceptor = new TransactionInterceptor();
 
+	@Nullable
 	private Pointcut pointcut;
 
 

spring-tx/src/main/java/org/springframework/transaction/jta/JtaTransactionManager.java

@@ -149,8 +149,10 @@ public class JtaTransactionManager extends AbstractPlatformTransactionManager
 
 	private transient JndiTemplate jndiTemplate = new JndiTemplate();
 
+	@Nullable
 	private transient UserTransaction userTransaction;
 
+	@Nullable
 	private String userTransactionName;
 
 	private boolean autodetectUserTransaction = true;
@@ -159,14 +161,18 @@ public class JtaTransactionManager extends AbstractPlatformTransactionManager
 
 	private boolean userTransactionObtainedFromJndi = false;
 
+	@Nullable
 	private transient TransactionManager transactionManager;
 
+	@Nullable
 	private String transactionManagerName;
 
 	private boolean autodetectTransactionManager = true;
 
+	@Nullable
 	private transient TransactionSynchronizationRegistry transactionSynchronizationRegistry;
 
+	@Nullable
 	private String transactionSynchronizationRegistryName;
 
 	private boolean autodetectTransactionSynchronizationRegistry = true;
@@ -743,8 +749,8 @@ public class JtaTransactionManager extends AbstractPlatformTransactionManager
 	 * @throws TransactionSystemException in case of errors
 	 */
 	@Nullable
-	protected TransactionSynchronizationRegistry findTransactionSynchronizationRegistry(UserTransaction ut, TransactionManager tm)
-			throws TransactionSystemException {
+	protected TransactionSynchronizationRegistry findTransactionSynchronizationRegistry(
+			@Nullable UserTransaction ut, @Nullable TransactionManager tm) throws TransactionSystemException {
 
 		if (this.userTransactionObtainedFromJndi) {
 			// UserTransaction has already been obtained from JNDI, so the

spring-tx/src/main/java/org/springframework/transaction/jta/SpringJtaSynchronizationAdapter.java

@@ -49,6 +49,7 @@ public class SpringJtaSynchronizationAdapter implements Synchronization {
 
 	private final TransactionSynchronization springSynchronization;
 
+	@Nullable
 	private UserTransaction jtaTransaction;
 
 	private boolean beforeCompletionCalled = false;

spring-tx/src/main/java/org/springframework/transaction/jta/WebLogicJtaTransactionManager.java

@@ -88,16 +88,21 @@ public class WebLogicJtaTransactionManager extends JtaTransactionManager {
 
 	private boolean weblogicUserTransactionAvailable;
 
+	@Nullable
 	private Method beginWithNameMethod;
 
+	@Nullable
 	private Method beginWithNameAndTimeoutMethod;
 
 	private boolean weblogicTransactionManagerAvailable;
 
+	@Nullable
 	private Method forceResumeMethod;
 
+	@Nullable
 	private Method setPropertyMethod;
 
+	@Nullable
 	private Object transactionHelper;
 
 
@@ -109,10 +114,10 @@ public class WebLogicJtaTransactionManager extends JtaTransactionManager {
 
 	@Override
 	protected UserTransaction retrieveUserTransaction() throws TransactionSystemException {
-		loadWebLogicTransactionHelper();
+		Object helper = loadWebLogicTransactionHelper();
 		try {
 			logger.debug("Retrieving JTA UserTransaction from WebLogic TransactionHelper");
-			Method getUserTransactionMethod = this.transactionHelper.getClass().getMethod("getUserTransaction");
+			Method getUserTransactionMethod = helper.getClass().getMethod("getUserTransaction");
 			return (UserTransaction) getUserTransactionMethod.invoke(this.transactionHelper);
 		}
 		catch (InvocationTargetException ex) {
@@ -127,10 +132,10 @@ public class WebLogicJtaTransactionManager extends JtaTransactionManager {
 
 	@Override
 	protected TransactionManager retrieveTransactionManager() throws TransactionSystemException {
-		loadWebLogicTransactionHelper();
+		Object helper = loadWebLogicTransactionHelper();
 		try {
 			logger.debug("Retrieving JTA TransactionManager from WebLogic TransactionHelper");
-			Method getTransactionManagerMethod = this.transactionHelper.getClass().getMethod("getTransactionManager");
+			Method getTransactionManagerMethod = helper.getClass().getMethod("getTransactionManager");
 			return (TransactionManager) getTransactionManagerMethod.invoke(this.transactionHelper);
 		}
 		catch (InvocationTargetException ex) {
@@ -143,12 +148,14 @@ public class WebLogicJtaTransactionManager extends JtaTransactionManager {
 		}
 	}
 
-	private void loadWebLogicTransactionHelper() throws TransactionSystemException {
-		if (this.transactionHelper == null) {
+	private Object loadWebLogicTransactionHelper() throws TransactionSystemException {
+		Object helper = this.transactionHelper;
+		if (helper == null) {
 			try {
 				Class<?> transactionHelperClass = getClass().getClassLoader().loadClass(TRANSACTION_HELPER_CLASS_NAME);
 				Method getTransactionHelperMethod = transactionHelperClass.getMethod("getTransactionHelper");
-				this.transactionHelper = getTransactionHelperMethod.invoke(null);
+				helper = getTransactionHelperMethod.invoke(null);
+				this.transactionHelper = helper;
 				logger.debug("WebLogic TransactionHelper found");
 			}
 			catch (InvocationTargetException ex) {
@@ -161,6 +168,7 @@ public class WebLogicJtaTransactionManager extends JtaTransactionManager {
 						ex);
 			}
 		}
+		return helper;
 	}
 
 	private void loadWebLogicTransactionClasses() throws TransactionSystemException {
@@ -220,6 +228,7 @@ public class WebLogicJtaTransactionManager extends JtaTransactionManager {
 					weblogic.transaction.UserTransaction wut = (weblogic.transaction.UserTransaction) ut;
 					wut.begin(definition.getName(), timeout);
 					*/
+					Assert.state(this.beginWithNameAndTimeoutMethod != null, "WebLogic JTA API not initialized");
 					this.beginWithNameAndTimeoutMethod.invoke(txObject.getUserTransaction(), definition.getName(), timeout);
 				}
 				else {
@@ -227,6 +236,7 @@ public class WebLogicJtaTransactionManager extends JtaTransactionManager {
 					weblogic.transaction.UserTransaction wut = (weblogic.transaction.UserTransaction) ut;
 					wut.begin(definition.getName());
 					*/
+					Assert.state(this.beginWithNameMethod != null, "WebLogic JTA API not initialized");
 					this.beginWithNameMethod.invoke(txObject.getUserTransaction(), definition.getName());
 				}
 			}
@@ -256,6 +266,7 @@ public class WebLogicJtaTransactionManager extends JtaTransactionManager {
 					weblogic.transaction.Transaction wtx = (weblogic.transaction.Transaction) tx;
 					wtx.setProperty(ISOLATION_LEVEL_KEY, isolationLevel);
 					*/
+					Assert.state(this.setPropertyMethod != null, "WebLogic JTA API not initialized");
 					this.setPropertyMethod.invoke(tx, ISOLATION_LEVEL_KEY, isolationLevel);
 				}
 				catch (InvocationTargetException ex) {
@@ -274,7 +285,7 @@ public class WebLogicJtaTransactionManager extends JtaTransactionManager {
 	}
 
 	@Override
-	protected void doJtaResume(JtaTransactionObject txObject, Object suspendedTransaction)
+	protected void doJtaResume(@Nullable JtaTransactionObject txObject, Object suspendedTransaction)
 			throws InvalidTransactionException, SystemException {
 
 		try {
@@ -295,6 +306,7 @@ public class WebLogicJtaTransactionManager extends JtaTransactionManager {
 			wtm.forceResume(suspendedTransaction);
 			*/
 			try {
+				Assert.state(this.forceResumeMethod != null, "WebLogic JTA API not initialized");
 				this.forceResumeMethod.invoke(getTransactionManager(), suspendedTransaction);
 			}
 			catch (InvocationTargetException ex2) {
@@ -313,9 +325,11 @@ public class WebLogicJtaTransactionManager extends JtaTransactionManager {
 		if (this.weblogicUserTransactionAvailable && name != null) {
 			try {
 				if (timeout >= 0) {
+					Assert.state(this.beginWithNameAndTimeoutMethod != null, "WebLogic JTA API not initialized");
 					this.beginWithNameAndTimeoutMethod.invoke(getUserTransaction(), name, timeout);
 				}
 				else {
+					Assert.state(this.beginWithNameMethod != null, "WebLogic JTA API not initialized");
 					this.beginWithNameMethod.invoke(getUserTransaction(), name);
 				}
 			}

spring-tx/src/main/java/org/springframework/transaction/jta/WebSphereUowTransactionManager.java

@@ -41,6 +41,7 @@ import org.springframework.transaction.support.TransactionCallback;
 import org.springframework.transaction.support.TransactionSynchronization;
 import org.springframework.transaction.support.TransactionSynchronizationManager;
 import org.springframework.transaction.support.TransactionSynchronizationUtils;
+import org.springframework.util.Assert;
 import org.springframework.util.ReflectionUtils;
 
 /**
@@ -96,8 +97,10 @@ public class WebSphereUowTransactionManager extends JtaTransactionManager
 	public static final String DEFAULT_UOW_MANAGER_NAME = "java:comp/websphere/UOWManager";
 
 
+	@Nullable
 	private UOWManager uowManager;
 
+	@Nullable
 	private String uowManagerName;
 
 
@@ -194,6 +197,12 @@ public class WebSphereUowTransactionManager extends JtaTransactionManager
 		}
 	}
 
+	private UOWManager obtainUOWManager() {
+		Assert.state(this.uowManager != null, "No UOWManager set");
+		return this.uowManager;
+	}
+
+
 	/**
 	 * Registers the synchronizations as interposed JTA Synchronization on the UOWManager.
 	 */
@@ -201,7 +210,7 @@ public class WebSphereUowTransactionManager extends JtaTransactionManager
 	protected void doRegisterAfterCompletionWithJtaTransaction(
 			JtaTransactionObject txObject, List<TransactionSynchronization> synchronizations) {
 
-		this.uowManager.registerInterposedSynchronization(new JtaAfterCompletionSynchronization(synchronizations));
+		obtainUOWManager().registerInterposedSynchronization(new JtaAfterCompletionSynchronization(synchronizations));
 	}
 
 	/**
@@ -231,9 +240,11 @@ public class WebSphereUowTransactionManager extends JtaTransactionManager
 		if (definition.getTimeout() < TransactionDefinition.TIMEOUT_DEFAULT) {
 			throw new InvalidTimeoutException("Invalid transaction timeout", definition.getTimeout());
 		}
+
+		UOWManager uowManager = obtainUOWManager();
 		int pb = definition.getPropagationBehavior();
-		boolean existingTx = (this.uowManager.getUOWStatus() != UOWSynchronizationRegistry.UOW_STATUS_NONE &&
-				this.uowManager.getUOWType() != UOWSynchronizationRegistry.UOW_TYPE_LOCAL_TRANSACTION);
+		boolean existingTx = (uowManager.getUOWStatus() != UOWSynchronizationRegistry.UOW_STATUS_NONE &&
+				uowManager.getUOWType() != UOWSynchronizationRegistry.UOW_TYPE_LOCAL_TRANSACTION);
 
 		int uowType = UOWSynchronizationRegistry.UOW_TYPE_GLOBAL_TRANSACTION;
 		boolean joinTx = false;
@@ -283,14 +294,14 @@ public class WebSphereUowTransactionManager extends JtaTransactionManager
 		SuspendedResourcesHolder suspendedResources = (!joinTx ? suspend(null) : null);
 		try {
 			if (definition.getTimeout() > TransactionDefinition.TIMEOUT_DEFAULT) {
-				this.uowManager.setUOWTimeout(uowType, definition.getTimeout());
+				uowManager.setUOWTimeout(uowType, definition.getTimeout());
 			}
 			if (debug) {
 				logger.debug("Invoking WebSphere UOW action: type=" + uowType + ", join=" + joinTx);
 			}
 			UOWActionAdapter<T> action = new UOWActionAdapter<>(
 					definition, callback, (uowType == UOWManager.UOW_TYPE_GLOBAL_TRANSACTION), !joinTx, newSynch, debug);
-			this.uowManager.runUnderUOW(uowType, joinTx, action);
+			uowManager.runUnderUOW(uowType, joinTx, action);
 			if (debug) {
 				logger.debug("Returned from WebSphere UOW action: type=" + uowType + ", join=" + joinTx);
 			}
@@ -327,12 +338,15 @@ public class WebSphereUowTransactionManager extends JtaTransactionManager
 
 		private boolean debug;
 
+		@Nullable
 		private T result;
 
+		@Nullable
 		private Throwable exception;
 
 		public UOWActionAdapter(TransactionDefinition definition, TransactionCallback<T> callback,
 				boolean actualTransaction, boolean newTransaction, boolean newSynchronization, boolean debug) {
+
 			this.definition = definition;
 			this.callback = callback;
 			this.actualTransaction = actualTransaction;
@@ -343,6 +357,7 @@ public class WebSphereUowTransactionManager extends JtaTransactionManager
 
 		@Override
 		public void run() {
+			UOWManager uowManager = obtainUOWManager();
 			DefaultTransactionStatus status = prepareTransactionStatus(
 					this.definition, (this.actualTransaction ? this : null),
 					this.newTransaction, this.newSynchronization, this.debug, null);
@@ -372,6 +387,7 @@ public class WebSphereUowTransactionManager extends JtaTransactionManager
 			}
 		}
 
+		@Nullable
 		public T getResult() {
 			if (this.exception != null) {
 				ReflectionUtils.rethrowRuntimeException(this.exception);
@@ -381,7 +397,7 @@ public class WebSphereUowTransactionManager extends JtaTransactionManager
 
 		@Override
 		public boolean isRollbackOnly() {
-			return uowManager.getRollbackOnly();
+			return obtainUOWManager().getRollbackOnly();
 		}
 
 		@Override

spring-tx/src/main/java/org/springframework/transaction/support/AbstractPlatformTransactionManager.java

@@ -1271,14 +1271,18 @@ public abstract class AbstractPlatformTransactionManager implements PlatformTran
 	 */
 	protected static class SuspendedResourcesHolder {
 
+		@Nullable
 		private final Object suspendedResources;
 
+		@Nullable
 		private List<TransactionSynchronization> suspendedSynchronizations;
 
+		@Nullable
 		private String name;
 
 		private boolean readOnly;
 
+		@Nullable
 		private Integer isolationLevel;
 
 		private boolean wasActive;

spring-tx/src/main/java/org/springframework/transaction/support/AbstractTransactionStatus.java

@@ -50,6 +50,7 @@ public abstract class AbstractTransactionStatus implements TransactionStatus {
 
 	private boolean completed = false;
 
+	@Nullable
 	private Object savepoint;
 
 

spring-tx/src/main/java/org/springframework/transaction/support/DefaultTransactionDefinition.java

@@ -19,6 +19,7 @@ package org.springframework.transaction.support;
 import java.io.Serializable;
 
 import org.springframework.core.Constants;
+import org.springframework.lang.Nullable;
 import org.springframework.transaction.TransactionDefinition;
 
 /**
@@ -59,6 +60,7 @@ public class DefaultTransactionDefinition implements TransactionDefinition, Seri
 
 	private boolean readOnly = false;
 
+	@Nullable
 	private String name;
 
 

spring-tx/src/main/java/org/springframework/transaction/support/DefaultTransactionStatus.java

@@ -50,6 +50,7 @@ import org.springframework.util.Assert;
  */
 public class DefaultTransactionStatus extends AbstractTransactionStatus {
 
+	@Nullable
 	private final Object transaction;
 
 	private final boolean newTransaction;
@@ -60,6 +61,7 @@ public class DefaultTransactionStatus extends AbstractTransactionStatus {
 
 	private final boolean debug;
 
+	@Nullable
 	private final Object suspendedResources;
 
 

spring-tx/src/main/java/org/springframework/transaction/support/ResourceHolderSupport.java

@@ -18,6 +18,7 @@ package org.springframework.transaction.support;
 
 import java.util.Date;
 
+import org.springframework.lang.Nullable;
 import org.springframework.transaction.TransactionTimedOutException;
 
 /**
@@ -38,6 +39,7 @@ public abstract class ResourceHolderSupport implements ResourceHolder {
 
 	private boolean rollbackOnly = false;
 
+	@Nullable
 	private Date deadline;
 
 	private int referenceCount = 0;
@@ -111,6 +113,7 @@ public abstract class ResourceHolderSupport implements ResourceHolder {
 	 * Return the expiration deadline of this object.
 	 * @return the deadline as Date object
 	 */
+	@Nullable
 	public Date getDeadline() {
 		return this.deadline;
 	}

spring-tx/src/main/java/org/springframework/transaction/support/TransactionTemplate.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2017 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.
@@ -22,11 +22,13 @@ import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
 import org.springframework.beans.factory.InitializingBean;
+import org.springframework.lang.Nullable;
 import org.springframework.transaction.PlatformTransactionManager;
 import org.springframework.transaction.TransactionDefinition;
 import org.springframework.transaction.TransactionException;
 import org.springframework.transaction.TransactionStatus;
 import org.springframework.transaction.TransactionSystemException;
+import org.springframework.util.Assert;
 
 /**
  * Template class that simplifies programmatic transaction demarcation and
@@ -66,6 +68,7 @@ public class TransactionTemplate extends DefaultTransactionDefinition
 	/** Logger available to subclasses */
 	protected final Log logger = LogFactory.getLog(getClass());
 
+	@Nullable
 	private PlatformTransactionManager transactionManager;
 
 
@@ -109,6 +112,7 @@ public class TransactionTemplate extends DefaultTransactionDefinition
 	/**
 	 * Return the transaction management strategy to be used.
 	 */
+	@Nullable
 	public PlatformTransactionManager getTransactionManager() {
 		return this.transactionManager;
 	}
@@ -123,6 +127,8 @@ public class TransactionTemplate extends DefaultTransactionDefinition
 
 	@Override
 	public <T> T execute(TransactionCallback<T> action) throws TransactionException {
+		Assert.state(this.transactionManager != null, "No PlatformTransactionManager set");
+
 		if (this.transactionManager instanceof CallbackPreferringPlatformTransactionManager) {
 			return ((CallbackPreferringPlatformTransactionManager) this.transactionManager).execute(this, action);
 		}
@@ -132,16 +138,11 @@ public class TransactionTemplate extends DefaultTransactionDefinition
 			try {
 				result = action.doInTransaction(status);
 			}
-			catch (RuntimeException ex) {
+			catch (RuntimeException | Error ex) {
 				// Transactional code threw application exception -> rollback
 				rollbackOnException(status, ex);
 				throw ex;
 			}
-			catch (Error err) {
-				// Transactional code threw error -> rollback
-				rollbackOnException(status, err);
-				throw err;
-			}
 			catch (Throwable ex) {
 				// Transactional code threw unexpected exception -> rollback
 				rollbackOnException(status, ex);
@@ -159,6 +160,8 @@ public class TransactionTemplate extends DefaultTransactionDefinition
 	 * @throws TransactionException in case of a rollback error
 	 */
 	private void rollbackOnException(TransactionStatus status, Throwable ex) throws TransactionException {
+		Assert.state(this.transactionManager != null, "No PlatformTransactionManager set");
+
 		logger.debug("Initiating transaction rollback on application exception", ex);
 		try {
 			this.transactionManager.rollback(status);