在这篇文章中，我们将带领您了解使用HibernateJPA2.1将应用程序部署到IBMWebSphere会产生NullPointerException的全貌，同时，我们还将为您介绍有关android–
在这篇文章中，我们将带领您了解使用Hibernate JPA 2.1将应用程序部署到IBM WebSphere会产生NullPointerException的全貌，同时，我们还将为您介绍有关android – 为什么使用标准BillingService会发生NullPointerException？、Boolean.valueOf（）有时会产生NullPointerException、Caused by: org.hibernate.HibernateException: Access to DialectResolutionInfo cannot be null when ...、ConcurrentHashMap 产生NullPointerException的知识，以帮助您更好地理解这个主题。
本文目录一览：- 使用Hibernate JPA 2.1将应用程序部署到IBM WebSphere会产生NullPointerException
- android – 为什么使用标准BillingService会发生NullPointerException？
- Boolean.valueOf（）有时会产生NullPointerException
- Caused by: org.hibernate.HibernateException: Access to DialectResolutionInfo cannot be null when ...
- ConcurrentHashMap 产生NullPointerException
使用Hibernate JPA 2.1将应用程序部署到IBM WebSphere会产生NullPointerException
我们正在尝试使用Hibernate将Java 7 Spring MVC应用程序部署到IBM WebSphere
8.5.5.2服务器中。该应用程序可以在Tomcat服务器上正常运行，但是我们无法使其在WebSphere中运行。
堆栈跟踪输出如下：
[3/26/15 13:49:53:552 MDT] 00000066 AutowiredAnno I org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor <init> JSR-330 ''javax.inject.Inject'' annotation found and supported for autowiring[3/26/15 13:49:54:299 MDT] 00000066 LocalContaine I org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean createNativeEntityManagerFactory Building JPA container EntityManagerFactory for persistence unit ''default''[3/26/15 13:49:54:339 MDT] 00000066 LogHelper Z org.hibernate.jpa.internal.util.LogHelper logPersistenceUnitInformation HHH000204: Processing PersistenceUnitInfo [ name: default ...][3/26/15 13:49:54:536 MDT] 00000066 Version Z org.hibernate.Version logVersion HHH000412: Hibernate Core {4.3.7.Final}[3/26/15 13:49:54:543 MDT] 00000066 Environment Z org.hibernate.cfg.Environment <clinit> HHH000206: hibernate.properties not found[3/26/15 13:49:54:546 MDT] 00000066 Environment Z org.hibernate.cfg.Environment buildBytecodeProvider HHH000021: Bytecode provider name : javassist[3/26/15 13:49:54:580 MDT] 00000066 JarInputStrea Z org.hibernate.jpa.boot.archive.internal.JarInputStreamBasedArchiveDescriptor visitArchive HHH015010: Unable to find file (ignored): bundleresource://130.fwk-1163147521/ java.lang.NullPointerException: in is null at java.util.zip.ZipInputStream.<init>(ZipInputStream.java:111) at java.util.zip.ZipInputStream.<init>(ZipInputStream.java:90) at java.util.jar.JarInputStream.<init>(JarInputStream.java:87) at java.util.jar.JarInputStream.<init>(JarInputStream.java:73) at org.hibernate.jpa.boot.archive.internal.JarInputStreamBasedArchiveDescriptor.visitArchive(JarInputStreamBasedArchiveDescriptor.java:73) at org.hibernate.jpa.boot.scan.spi.AbstractScannerImpl.scan(AbstractScannerImpl.java:72) at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.scan(EntityManagerFactoryBuilderImpl.java:725) at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.<init>(EntityManagerFactoryBuilderImpl.java:221) at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.<init>(EntityManagerFactoryBuilderImpl.java:188) at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider$1.<init>(SpringHibernateJpaPersistenceProvider.java:49) at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider.createContainerEntityManagerFactory(SpringHibernateJpaPersistenceProvider.java:49) at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:343) at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:318) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1627) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1564) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:540) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:476) at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:302) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:229) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:298) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:193) at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:956) at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:747) at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:480) at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:403) at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:306) at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:106) at com.ibm.ws.webcontainer.webapp.WebApp.notifyServletContextCreated(WebApp.java:1686) at com.ibm.ws.webcontainer.webapp.WebAppImpl.initialize(WebAppImpl.java:414) at com.ibm.ws.webcontainer.webapp.WebGroupImpl.addWebApplication(WebGroupImpl.java:88) at com.ibm.ws.webcontainer.VirtualHostImpl.addWebApplication(VirtualHostImpl.java:169) at com.ibm.ws.webcontainer.WSWebContainer.addWebApp(WSWebContainer.java:749) at com.ibm.ws.webcontainer.WSWebContainer.addWebApplication(WSWebContainer.java:634) at com.ibm.ws.webcontainer.component.WebContainerImpl.install(WebContainerImpl.java:426) at com.ibm.ws.webcontainer.component.WebContainerImpl.start(WebContainerImpl.java:718) at com.ibm.ws.runtime.component.ApplicationMgrImpl.start(ApplicationMgrImpl.java:1177) at com.ibm.ws.runtime.component.DeployedApplicationImpl.fireDeployedObjectStart(DeployedApplicationImpl.java:1370) at com.ibm.ws.runtime.component.DeployedModuleImpl.start(DeployedModuleImpl.java:639) at com.ibm.ws.runtime.component.DeployedApplicationImpl.start(DeployedApplicationImpl.java:968) at com.ibm.ws.runtime.component.ApplicationMgrImpl.startApplication(ApplicationMgrImpl.java:776) at com.ibm.ws.runtime.component.ApplicationMgrImpl$5.run(ApplicationMgrImpl.java:2195) at com.ibm.ws.security.auth.ContextManagerImpl.runAs(ContextManagerImpl.java:5474) at com.ibm.ws.security.auth.ContextManagerImpl.runAsSystem(ContextManagerImpl.java:5600) at com.ibm.ws.security.core.SecurityContext.runAsSystem(SecurityContext.java:255) at com.ibm.ws.runtime.component.ApplicationMgrImpl.start(ApplicationMgrImpl.java:2200) at com.ibm.ws.runtime.component.CompositionUnitMgrImpl.start(CompositionUnitMgrImpl.java:446) at com.ibm.ws.runtime.component.CompositionUnitImpl.start(CompositionUnitImpl.java:123) at com.ibm.ws.runtime.component.CompositionUnitMgrImpl.start(CompositionUnitMgrImpl.java:389) at com.ibm.ws.runtime.component.CompositionUnitMgrImpl.access$500(CompositionUnitMgrImpl.java:117) at com.ibm.ws.runtime.component.CompositionUnitMgrImpl$CUInitializer.run(CompositionUnitMgrImpl.java:995) at com.ibm.wsspi.runtime.component.WsComponentImpl$_AsynchInitializer.run(WsComponentImpl.java:502) at com.ibm.ws.util.ThreadPool$Worker.run(ThreadPool.java:1864)[3/26/15 13:49:54:899 MDT] 00000066 Version Z org.hibernate.annotations.common.reflection.java.JavaReflectionManager <clinit> HCANN000001: Hibernate Commons Annotations {4.0.5.Final}[3/26/15 13:49:55:511 MDT] 00000066 Enhance E CWWJP9992E: openjpa.Enhance: Error: The identity field defined in the com.company.model.KeyValueMapping Embeddable is not supported. [3/26/15 13:49:55:837 MDT] 00000066 Dialect Z org.hibernate.dialect.Dialect <init> HHH000400: Using dialect: org.hibernate.dialect.SQLServer2008Dialect[3/26/15 13:49:55:864 MDT] 00000066 LobCreatorBui Z org.hibernate.engine.jdbc.internal.LobCreatorBuilder useContextualLobCreation HHH000423: Disabling contextual LOB creation as JDBC driver reported JDBC version [3] less than 4[3/26/15 13:49:56:071 MDT] 00000066 AnnotationCon W org.springframework.context.support.AbstractApplicationContext refresh Exception encountered during context initialization - cancelling refresh attempt org.springframework.beans.factory.BeanCreationException: Error creating bean with name ''entityManagerFactory'' defined in com.company.WebConfig: Invocation of init method failed; nested exception is java.lang.NoSuchMethodError: javax/persistence/Table.indexes()[Ljavax/persistence/Index; at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1568) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:540) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:476) at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:302) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:229) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:298) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:193) at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:956) at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:747) at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:480) at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:403) at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:306) at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:106) at com.ibm.ws.webcontainer.webapp.WebApp.notifyServletContextCreated(WebApp.java:1686) at com.ibm.ws.webcontainer.webapp.WebAppImpl.initialize(WebAppImpl.java:414) at com.ibm.ws.webcontainer.webapp.WebGroupImpl.addWebApplication(WebGroupImpl.java:88) at com.ibm.ws.webcontainer.VirtualHostImpl.addWebApplication(VirtualHostImpl.java:169) at com.ibm.ws.webcontainer.WSWebContainer.addWebApp(WSWebContainer.java:749) at com.ibm.ws.webcontainer.WSWebContainer.addWebApplication(WSWebContainer.java:634) at com.ibm.ws.webcontainer.component.WebContainerImpl.install(WebContainerImpl.java:426) at com.ibm.ws.webcontainer.component.WebContainerImpl.start(WebContainerImpl.java:718) at com.ibm.ws.runtime.component.ApplicationMgrImpl.start(ApplicationMgrImpl.java:1177) at com.ibm.ws.runtime.component.DeployedApplicationImpl.fireDeployedObjectStart(DeployedApplicationImpl.java:1370) at com.ibm.ws.runtime.component.DeployedModuleImpl.start(DeployedModuleImpl.java:639) at com.ibm.ws.runtime.component.DeployedApplicationImpl.start(DeployedApplicationImpl.java:968) at com.ibm.ws.runtime.component.ApplicationMgrImpl.startApplication(ApplicationMgrImpl.java:776) at com.ibm.ws.runtime.component.ApplicationMgrImpl$5.run(ApplicationMgrImpl.java:2195) at com.ibm.ws.security.auth.ContextManagerImpl.runAs(ContextManagerImpl.java:5474) at com.ibm.ws.security.auth.ContextManagerImpl.runAsSystem(ContextManagerImpl.java:5600) at com.ibm.ws.security.core.SecurityContext.runAsSystem(SecurityContext.java:255) at com.ibm.ws.runtime.component.ApplicationMgrImpl.start(ApplicationMgrImpl.java:2200) at com.ibm.ws.runtime.component.CompositionUnitMgrImpl.start(CompositionUnitMgrImpl.java:446) at com.ibm.ws.runtime.component.CompositionUnitImpl.start(CompositionUnitImpl.java:123) at com.ibm.ws.runtime.component.CompositionUnitMgrImpl.start(CompositionUnitMgrImpl.java:389) at com.ibm.ws.runtime.component.CompositionUnitMgrImpl.access$500(CompositionUnitMgrImpl.java:117) at com.ibm.ws.runtime.component.CompositionUnitMgrImpl$CUInitializer.run(CompositionUnitMgrImpl.java:995) at com.ibm.wsspi.runtime.component.WsComponentImpl$_AsynchInitializer.run(WsComponentImpl.java:502) at com.ibm.ws.util.ThreadPool$Worker.run(ThreadPool.java:1864)Caused by: java.lang.NoSuchMethodError: javax/persistence/Table.indexes()[Ljavax/persistence/Index; at org.hibernate.cfg.annotations.EntityBinder.processComplementaryTableDefinitions(EntityBinder.java:973) at org.hibernate.cfg.AnnotationBinder.bindClass(AnnotationBinder.java:824) at org.hibernate.cfg.Configuration$MetadataSourceQueue.processAnnotatedClassesQueue(Configuration.java:3845) at org.hibernate.cfg.Configuration$MetadataSourceQueue.processMetadata(Configuration.java:3799) at org.hibernate.cfg.Configuration.secondPassCompile(Configuration.java:1412) at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1846) at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl$4.perform(EntityManagerFactoryBuilderImpl.java:852) at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl$4.perform(EntityManagerFactoryBuilderImpl.java:845) at org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl.withTccl(ClassLoaderServiceImpl.java:398) at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:844) at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider.createContainerEntityManagerFactory(SpringHibernateJpaPersistenceProvider.java:60) at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:343) at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:318) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1627) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1564) ... 37 more谢谢！
答案1
小编典典的javax/persistence/Table.indexes()是从2.1 JPA，WebSphere应用服务器传统8.5.5.2被默认JPA
2.0（OpenJPA中）使用。如果要使用Hibernate，则必须覆盖默认提供程序-
更新
是的，你是对的。您不能使用JPA 2.1覆盖WebSphere传统8.5.5.x中的默认提供程序，因为容器依赖于2.0 API进行初始化。
如果必须使用2.1，则可以将其用作应用程序托管的提供程序，而不是容器托管的。因此，您将需要为您的应用程序禁用JPA，进行检查，而不是依赖容器来注入EntityManager，而是使用API自行对其进行初始化。
另一个选择是考虑从版本8.5.5.6开始支持JPA 2.1（使用EclipseLink）的WebSphere
Liberty。由于容器支持2.1，应该可以在那里更改提供程序，但是我没有时间对其进行测试。
您还可以升级到最近发布的WebSphere Application Server v9，该版本支持JPA 2.1。
android – 为什么使用标准BillingService会发生NullPointerException？
我在我的应用程序中使用标准BillingService(即从sample application复制而不做更改).
但有时我的应用程序崩溃与logcat中的以下数据：
04-16 10:05:43.556: INFO/ActivityManager(96): Start proc tv.kinobaza.app for service tv.kinobaza.app/tv.kinobaza.billing.BillingService: pid=28748 uid=10081 gids={3003}
04-16 10:05:43.646: DEBUG/AndroidRuntime(28748): Shutting down VM
04-16 10:05:43.656: WARN/dalvikvm(28748): threadid=1: thread exiting with uncaught exception (group=0x400259f8)
04-16 10:05:43.656: ERROR/AndroidRuntime(28748): FATAL EXCEPTION: main
04-16 10:05:43.656: ERROR/AndroidRuntime(28748): java.lang.RuntimeException: Unable to start service tv.kinobaza.billing.BillingService@4632f578 with null: java.lang.NullPointerException
04-16 10:05:43.656: ERROR/AndroidRuntime(28748): at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:3282)
04-16 10:05:43.656: ERROR/AndroidRuntime(28748): at android.app.ActivityThread.access$3600(ActivityThread.java:135)
04-16 10:05:43.656: ERROR/AndroidRuntime(28748): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2211)
04-16 10:05:43.656: ERROR/AndroidRuntime(28748): at android.os.Handler.dispatchMessage(Handler.java:99)
04-16 10:05:43.656: ERROR/AndroidRuntime(28748): at android.os.Looper.loop(Looper.java:144)
04-16 10:05:43.656: ERROR/AndroidRuntime(28748): at android.app.ActivityThread.main(ActivityThread.java:4937)
04-16 10:05:43.656: ERROR/AndroidRuntime(28748): at java.lang.reflect.Method.invokeNative(Native Method)
04-16 10:05:43.656: ERROR/AndroidRuntime(28748): at java.lang.reflect.Method.invoke(Method.java:521)
04-16 10:05:43.656: ERROR/AndroidRuntime(28748): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
04-16 10:05:43.656: ERROR/AndroidRuntime(28748): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
04-16 10:05:43.656: ERROR/AndroidRuntime(28748): at dalvik.system.NativeStart.main(Native Method)
04-16 10:05:43.656: ERROR/AndroidRuntime(28748): Caused by: java.lang.NullPointerException
04-16 10:05:43.656: ERROR/AndroidRuntime(28748): at tv.kinobaza.billing.BillingService.onStart(UnkNown Source)
04-16 10:05:43.656: ERROR/AndroidRuntime(28748): at android.app.Service.onStartCommand(Service.java:420)
04-16 10:05:43.656: ERROR/AndroidRuntime(28748): at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:3267)
04-16 10:05:43.656: ERROR/AndroidRuntime(28748): ... 10 more
04-16 10:05:43.736: DEBUG/SurfaceFlinger(96): Layer::setBuffers(this=0xb947a8),pid=96,w=1,h=1
04-16 10:05:43.736: DEBUG/SurfaceFlinger(96): Layer::setBuffers(this=0xb947a8),h=1
04-16 10:05:43.766: DEBUG/SurfaceFlinger(96): Layer::requestBuffer(this=0xb947a8),index=0,w=480,h=418 success
04-16 10:05:43.986: DEBUG/dalvikvm(28721): GC_FOR_MALLOC freed 9604 objects / 1369120 bytes in 102ms
这是相关的代码：
/**
* We don't support binding to this service,only starting the service.
*/
@Override
public IBinder onBind(Intent intent) {
return null;
}
@Override
public void onStart(Intent intent,int startId) {
handleCommand(intent,startId);
}
这有什么不对？
我注意到了 – 当设备在夜间睡觉时,一旦我开始使用它,它会在约5分钟内崩溃.
并且,以下是更多详细信息：BillingService从我的应用程序的“首选项”屏幕开始.这里是Preferences类的代码：
@Override
protected void onDestroy() {
mBillingService.unbind();
super.onDestroy();
}
UPD.也许,我应该在Main活动中启动此服务/解除绑定？
这是我的proguard.cfg：
-optimizationpasses 5
-dontusemixedcaseclassnames
-dontskipnonpubliclibraryclasses
-dontpreverify
-verbose
-optimizations !code/simplification/arithmetic,!field/*,!class/merging/*
-keep public class * extends android.app.Activity
-keep public class * extends android.app.Application
-keep public class * extends android.app.Service
-keep public class * extends android.content.broadcastReceiver
-keep public class * extends android.content.ContentProvider
-keep public class * extends android.app.backup.BackupAgentHelper
-keep public class * extends android.preference.Preference
-keep public class com.android.vending.licensing.ILicensingService
-keep class com.android.vending.billing.**
-keepclasseswithmembernames class * {
native java.lang.String);
}
-keep class * implements android.os.Parcelable {
public static final android.os.Parcelable$Creator *;
}
-libraryjars /lib/libGoogleAnalytics.jar
-libraryjars /lib/signpost-commonshttp4-1.2.1.1.jar
-libraryjars /lib/signpost-core-1.2.1.1.jar
-dontwarn org.apache.commons.codec.binary.Base64
最佳答案
所以你在proguard之后得到这个NPE而不是事先.
你必须混淆一些你不应该喜欢扩展应用程序/活动/服务的类
你不应该混淆这些类：
http://proguard.sourceforge.net/index.html#/manual/examples.html(转到例7)
Boolean.valueOf（）有时会产生NullPointerException
我有这个代码：
package tests;import java.util.Hashtable;public class Tests { public static void main(String[] args) { Hashtable<String, Boolean> modifiedItems = new Hashtable<String, Boolean>(); System.out.println("TEST 1"); System.out.println(modifiedItems.get("item1")); // Prints null System.out.println("TEST 2"); System.out.println(modifiedItems.get("item1") == null); // Prints true System.out.println("TEST 3"); System.out.println(Boolean.valueOf(null)); // Prints false System.out.println("TEST 4"); System.out.println(Boolean.valueOf(modifiedItems.get("item1"))); // Produces NullPointerException System.out.println("FINISHED!"); // Never executed }}我的问题是我不明白为什么 Test 3 可以正常工作（它打印false并且不产生NullPointerException），而 Test
4却 抛出了NullPointerException。正如你可以看到测试 1 和 2
，null和modifiedItems.get("item1")是平等的和null。
Java 7和8中的行为相同。
答案1
小编典典您必须仔细查看正在调用的重载：
Boolean.valueOf(null)正在调用Boolean.valueOf(String)。NPE即使提供了null参数，也不会抛出“ even”。Boolean.valueOf(modifiedItems.get("item1"))正在调用Boolean.valueOf(boolean)，因为modifiedItems的值类型为Boolean，需要进行拆箱转换。既然modifiedItems.get("item1")是null，那就是该值的拆箱-而不是Boolean.valueOf(...)-引发NPE。
确定调用哪个重载的规则非常繁琐，但它们大致如下：
在第一遍中，搜索方法匹配项而不允许装箱/拆箱（也不使用可变Arity方法）。
- 因为
null是一个可接受的值String而不是boolean，在此过程中Boolean.valueOf(null)匹配Boolean.valueOf(String)； Boolean是Boolean.valueOf(String)或都不可接受的Boolean.valueOf(boolean)，因此在此传递中没有方法匹配Boolean.valueOf(modifiedItems.get("item1"))。在第二遍中，搜索方法匹配项，以允许装箱/拆箱（但仍然不是可变arity方法）。
Boolean可以将A 拆箱boolean，因此在此过程中Boolean.valueOf(boolean)与匹配Boolean.valueOf(modifiedItems.get("item1"))；但是编译器必须插入拆箱转换才能调用它：Boolean.valueOf(modifiedItems.get("item1").booleanValue())- （第三遍允许使用可变Arity方法，但此处不相关，因为前两个遍历与这些情况匹配）
- 因为
Caused by: org.hibernate.HibernateException: Access to DialectResolutionInfo cannot be null when ...
java.lang.IllegalStateException: Failed to load ApplicationContext
at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:125)
at org.springframework.test.context.support.DefaultTestContext.getApplicationContext(DefaultTestContext.java:108)
at org.springframework.test.context.web.ServletTestExecutionListener.setUpRequestContextIfNecessary(ServletTestExecutionListener.java:190)
at org.springframework.test.context.web.ServletTestExecutionListener.prepareTestInstance(ServletTestExecutionListener.java:132)
at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:246)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.createTest(SpringJUnit4ClassRunner.java:227)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner$1.runReflectiveCall(SpringJUnit4ClassRunner.java:289)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.methodBlock(SpringJUnit4ClassRunner.java:291)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:246)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:97)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:190)
at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:47)
at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)
at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name ''entityManagerFactory'' defined in class path resource [org/springframework/boot/autoconfigure/orm/jpa/HibernateJpaConfiguration.class]: Invocation of init method failed; nested exception is org.hibernate.service.spi.ServiceException: Unable to create requested service [org.hibernate.engine.jdbc.env.spi.JdbcEnvironment]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1778)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:593)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:515)
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:320)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:318)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199)
at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1105)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:867)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:549)
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:744)
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:391)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:312)
at org.springframework.boot.test.context.SpringBootContextLoader.loadContext(SpringBootContextLoader.java:120)
at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContextInternal(DefaultCacheAwareContextLoaderDelegate.java:99)
at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:117)
... 24 more
Caused by: org.hibernate.service.spi.ServiceException: Unable to create requested service [org.hibernate.engine.jdbc.env.spi.JdbcEnvironment]
at org.hibernate.service.internal.AbstractServiceRegistryImpl.createService(AbstractServiceRegistryImpl.java:275)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:237)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:214)
at org.hibernate.id.factory.internal.DefaultIdentifierGeneratorFactory.injectServices(DefaultIdentifierGeneratorFactory.java:152)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.injectDependencies(AbstractServiceRegistryImpl.java:286)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:243)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:214)
at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.<init>(InFlightMetadataCollectorImpl.java:179)
at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete(MetadataBuildingProcess.java:119)
at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.metadata(EntityManagerFactoryBuilderImpl.java:904)
at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:935)
at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider.createContainerEntityManagerFactory(SpringHibernateJpaPersistenceProvider.java:57)
at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:365)
at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.buildNativeEntityManagerFactory(AbstractEntityManagerFactoryBean.java:390)
at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:377)
at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.afterPropertiesSet(LocalContainerEntityManagerFactoryBean.java:341)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1837)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1774)
... 39 more
Caused by: org.hibernate.HibernateException: Access to DialectResolutionInfo cannot be null when ''hibernate.dialect'' not set
at org.hibernate.engine.jdbc.dialect.internal.DialectFactoryImpl.determineDialect(DialectFactoryImpl.java:100)
at org.hibernate.engine.jdbc.dialect.internal.DialectFactoryImpl.buildDialect(DialectFactoryImpl.java:54)
at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.initiateService(JdbcEnvironmentInitiator.java:137)
at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.initiateService(JdbcEnvironmentInitiator.java:35)
at org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.initiateService(StandardServiceRegistryImpl.java:94)
at org.hibernate.service.internal.AbstractServiceRegistryImpl.createService(AbstractServiceRegistryImpl.java:263)
... 56 more第一次使用 springboot+jpa 进行操作数据库，刚启动就爆出来异常:
应该在 yml 配置文件中加上:
spring:
jpa:
show-sql: true
hibernate:
ddl-auto: create
database-platform: org.hibernate.dialect.PostgreSQLDialect
ConcurrentHashMap 产生NullPointerException
今天测试在发给我一段报错日志后，根据日志定位到从ConcurrentHashMap 的缓存中get的时候，ConcurrentHashMap的底层抛出了空指针，当时感觉很奇怪为什么在get的时候产生空指针了呢？
模拟代码：
ConcurrentHashMap concurrentHashMap = new ConcurrentHashMap();
........................................................
concurrentHashMap.get(传入的参数)；这个地方出现空指针，难道是传入的null 所以出现了空指针了，事实证明确实传入了null，但是我记得hashmap 是可以传入null 的呀？ 为什么ConcurrentHashMap 却不行呢？
相应的去验证了一下，remove 方法发现也不能传入null 进去。
一、异常分析
FATAL EXCEPTION: main
java.lang.NullPointerException
at java.util.concurrent.ConcurrentHashMap.remove(ConcurrentHashMap.java:921)本以为是并发异常，后发现不对，因为ConcurrentHashMap已经使用继承自ReentrantLock的Segment，保证了线程安全，Java如果有这么大的bug肯定早修复了。看了下源码
发现自己大意了，在获取hashCode时NPE(hashMap不会，因为它会对null key做一次处理)。ConcurrentHashMap不接受null key和null value这个常识一时疏忽了，调用的地方确实有可能传入null。这样在remove前进行null判断即可解决。
在问题解决后，想到hashMap和linkedhashMap都允许null key和null value，treeMap不允许null key，但允许null value，而ConcurrentHashMap既不允许null key也不允许null value，why？
二、not allow null key and value
stackoverflow并结合了源码分析了一下
(1) treeMap不允许null key是因为compare会导致NPE, 可通过以下代码实现null key支持
SortedMap<Integer, Integer> map = new TreeMap<Integer, Integer>(new Comparator<Integer>() {
@Override
public int compare(Integer arg0, Integer arg1) {
if (arg0 == null) {
if (arg1 == null) return 0;
return -1;
}
if (arg1 == null) return 1;
return arg0.compareTo(arg1);
}
});(2) ConcurrentHashMap不允许null key和null value，是因为ConcurrentHashMap的锁机制
对于get(Object key)如果返回null，ConcurrentHashMap没办法判断是key不存在还是value就是null。有人得问了那么hashmap呢, 为什么可以，hashmap我们可以通过下面代码实现判断
Map<String, String> map = Collections.synchronizedMap(new HashMap<String, String>());
String key = "aa", value;
synchronized (map) {
if (map.containsKey(key)) {
value = map.get(key);
} else {
throw new Exception("key is not exist");
}
}使用Collections.synchronizedMap对hashmap加锁，Collections.synchronizedMap的锁是同步锁，就是对象本身，所以synchronized (map)与Collections.synchronizedMap内锁统一。而ConcurrentHashMap的并发控制是利用分离锁实现的(16个重入锁)，在外部无法获得锁，自己也没有提供函数进行判断，所以无奈了。
那么有没有办法既保证map的并发安全同时又允许null key和null value呢，当然了，两种方式
第一种实际上面已经展现了，通过Collections.synchronizedMap对hashmap加锁即可。synchronizedMap保证了线程安全，hashmap又允许null key和null value。
不过Collections.synchronizedMap的并发性能自然比不上ConcurrentHashMap的分桶锁机制，如果对性能要求较高
理论上也可以重写ConcurrentHashMap添加一个函数支持上面代码段的并发，但这个要求对ConcurrentHashMap的分离锁相当熟悉
最后：
关于为什么这么设计：
https://laiqitech.com/125/
关于null的一些小知识：
http://www.importnew.com/14229.html
今天关于使用Hibernate JPA 2.1将应用程序部署到IBM WebSphere会产生NullPointerException的介绍到此结束，谢谢您的阅读，有关android – 为什么使用标准BillingService会发生NullPointerException？、Boolean.valueOf（）有时会产生NullPointerException、Caused by: org.hibernate.HibernateException: Access to DialectResolutionInfo cannot be null when ...、ConcurrentHashMap 产生NullPointerException等更多相关知识的信息可以在本站进行查询。
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