我的申请听着 kafka 主题并将数据转储到 cassandra . 线程从 mongo 我也是。滞后 kafka 主题越来越多。我看到大多数线程在加载某些类时被阻塞。我把我的 thread_dump 在下面。

"KafkaConsumer-49" prio=10 tid=0x00007f1178fdd000 nid=0x78e0 waiting for monitor entry [0x00007f1155fb5000]
   java.lang.Thread.State: BLOCKED (on object monitor)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:403)
        - waiting to lock <0x00000006c0655b58> (a java.lang.Object)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:356)
        at org.springframework.util.ClassUtils.forName(ClassUtils.java:258)
        at org.springframework.data.convert.SimpleTypeInformationMapper.resolveTypeFrom(SimpleTypeInformationMapper.java:56)
        at org.springframework.data.convert.DefaultTypeMapper.readType(DefaultTypeMapper.java:103)
        at org.springframework.data.convert.DefaultTypeMapper.getDefaultedTypeToBeUsed(DefaultTypeMapper.java:144)
        at org.springframework.data.convert.DefaultTypeMapper.readType(DefaultTypeMapper.java:121)
        at org.springframework.data.mongodb.core.convert.MappingMongoConverter.read(MappingMongoConverter.java:186)
        at org.springframework.data.mongodb.core.convert.MappingMongoConverter.read(MappingMongoConverter.java:176)
        at org.springframework.data.mongodb.core.convert.MappingMongoConverter.read(MappingMongoConverter.java:172)
        at org.springframework.data.mongodb.core.convert.MappingMongoConverter.read(MappingMongoConverter.java:75)
        at org.springframework.data.mongodb.core.MongoTemplate$ReadDbObjectCallback.doWith(MongoTemplate.java:1840)
        at org.springframework.data.mongodb.core.MongoTemplate.executeFindMultiInternal(MongoTemplate.java:1536)
        at org.springframework.data.mongodb.core.MongoTemplate.doFind(MongoTemplate.java:1336)
        at org.springframework.data.mongodb.core.MongoTemplate.doFind(MongoTemplate.java:1322)
        at org.springframework.data.mongodb.core.MongoTemplate.find(MongoTemplate.java:495)
        at org.springframework.data.mongodb.core.MongoTemplate.find(MongoTemplate.java:486)
        at com.snapdeal.coms.timemachine.mao.TimeMachineMao.getVendorProductsForUploadId(TimeMachineMao.java:32)
        at com.snapdeal.coms.timemachine.service.TimeMachineService.getVendorProductsForUploadIdAndSupc(TimeMachineService.java:35)
        at com.snapdeal.coms.timemachine.event.SupcUploadIdStateUpdateEventHandler.handleEvent(SupcUploadIdStateUpdateEventHandler.java:40)

KafkaConsumer-48" prio=10 tid=0x00007f1178fdb000 nid=0x78df waiting for monitor entry [0x00007f11560b6000]
   java.lang.Thread.State: BLOCKED (on object monitor)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:403)
        - waiting to lock <0x00000006c0655b58> (a java.lang.Object)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:356)
        at org.springframework.util.ClassUtils.forName(ClassUtils.java:258)
        at org.springframework.data.convert.SimpleTypeInformationMapper.resolveTypeFrom(SimpleTypeInformationMapper.java:56)
        at org.springframework.data.convert.DefaultTypeMapper.readType(DefaultTypeMapper.java:103)
        at org.springframework.data.convert.DefaultTypeMapper.getDefaultedTypeToBeUsed(DefaultTypeMapper.java:144)
        at org.springframework.data.convert.DefaultTypeMapper.readType(DefaultTypeMapper.java:121)
        at org.springframework.data.mongodb.core.convert.MappingMongoConverter.read(MappingMongoConverter.java:186)
        at org.springframework.data.mongodb.core.convert.MappingMongoConverter.read(MappingMongoConverter.java:176)
        at org.springframework.data.mongodb.core.convert.MappingMongoConverter.read(MappingMongoConverter.java:172)
        at org.springframework.data.mongodb.core.convert.MappingMongoConverter.read(MappingMongoConverter.java:75)
        at org.springframework.data.mongodb.core.MongoTemplate$ReadDbObjectCallback.doWith(MongoTemplate.java:1840)
        at org.springframework.data.mongodb.core.MongoTemplate.executeFindMultiInternal(MongoTemplate.java:1536)
        at org.springframework.data.mongodb.core.MongoTemplate.doFind(MongoTemplate.java:1336)
        at org.springframework.data.mongodb.core.MongoTemplate.doFind(MongoTemplate.java:1322)
        at org.springframework.data.mongodb.core.MongoTemplate.find(MongoTemplate.java:495)
        at org.springframework.data.mongodb.core.MongoTemplate.find(MongoTemplate.java:486)
        at com.snapdeal.coms.timemachine.mao.TimeMachineMao.getVendorProductsForUploadId(TimeMachineMao.java:32)
        at com.snapdeal.coms.timemachine.service.TimeMachineService.getVendorProductsForUploadIdAndSupc(TimeMachineService.java:35)
        at com.snapdeal.coms.timemachine.event.SupcUploadIdStateUpdateEventHandler.handleEvent(SupcUploadIdStateUpdateEventHandler.java:40)
        at com.snapdeal.coms.timemachine.TimeMachine.onEvent(TimeMachine.java:109)

“kafkaconsumer-47”prio=10 tid=0x00007f1178fd9800 nid=0x78de等待监视器条目[0x00007f11561b7000]java.lang.thread.state:在java.lang.classloader.loadclass（classloader）处阻塞（在对象监视器上）。java:403)-正在等待在sun.misc.launcher$appclassloader.loadclass（launcher）锁定<0x00000006c0655b58>（java.lang.object）。java:308)在java.lang.classloader.loadclass（类加载器。java:356)在org.springframework.util.classutils.forname（classutils。java:258)位于org.springframework.data.convert.simpletypeinformationmapper.resolvetypefrom（simpletypeinformationmapper）。java:56)在org.springframework.data.convert.defaulttypemapper.readtype（defaulttypemapper。java:103)在org.springframework.data.convert.defaulttypemapper.getdefaultedtypetobeused（defaulttypemapper。java:144)在org.springframework.data.convert.defaulttypemapper.readtype（defaulttypemapper。java:121)在org.springframework.data.mongodb.core.convert.mappingmongoconverter.read（mappingmongoconverter。java:186)在org.springframework.data.mongodb.core.convert.mappingmongoconverter.read（mappingmongoconverter。java:176)在org.springframework.data.mongodb.core.convert.mappingmongoconverter.read（mappingmongoconverter。java:172)在org.springframework.data.mongodb.core.convert.mappingmongoconverter.read（mappingmongoconverter。java:75)在org.springframework.data.mongodb.core.mongotemplate$readdbobjectcallback.dowith（mongotemplate。java:1840)在org.springframework.data.mongodb.core.mongotemplate.executefindmultiinternal（mongotemplate。java:1536)在org.springframework.data.mongodb.core.mongotemplate.dofind（mongotemplate。java:1336)在org.springframework.data.mongodb.core.mongotemplate.dofind（mongotemplate。java:1322)在org.springframework.data.mongodb.core.mongotemplate.find（mongotemplate。java:495)在org.springframework.data.mongodb.core.mongotemplate.find（mongotemplate。java:486)

"KafkaConsumer-46" prio=10 tid=0x00007f1178fd8000 nid=0x78dd waiting for monitor entry [0x00007f11562b8000]

java.lang.thread.state:在java.lang.classloader.loadclass（classloader。java:403)-正在等待在sun.misc.launcher$appclassloader.loadclass（launcher）锁定<0x00000006c0655b58>（java.lang.object）。java:308)在java.lang.classloader.loadclass（classloader。java:356)在org.springframework.util.classutils.forname（classutils。java:258)位于org.springframework.data.convert.simpletypeinformationmapper.resolvetypefrom（simpletypeinformationmapper）。java:56)在org.springframework.data.convert.defaulttypemapper.readtype（defaulttypemapper。java:103)在org.springframework.data.convert.defaulttypemapper.getdefaultedtypetobeused（defaulttypemapper。java:144)在org.springframework.data.convert.defaulttypemapper.readtype（defaulttypemapper。java:121)在org.springframework.data.mongodb.core.convert.mappingmongoconverter.read（mappingmongoconverter。java:186)在org.springframework.data.mongodb.core.convert.mappingmongoconverter.read（mappingmongoconverter。java:176)在org.springframework.data.mongodb.core.convert.mappingmongoconverter.read（mappingmongoconverter。java:172)在org.springframework.data.mongodb.core.convert.mappingmongoconverter.read（mappingmongoconverter。java:75)在org.springframework.data.mongodb.core.mongotemplate$readdbobjectcallback.dowith（mongotemplate。java:1840)在org.springframework.data.mongodb.core.mongotemplate.executefindmultiinternal（mongotemplate。java:1536)在org.springframework.data.mongodb.core.mongotemplate.dofind（mongotemplate。java:1336)在org.springframework.data.mongodb.core.mongotemplate.dofind（mongotemplate。java:1322)在org.springframework.data.mongodb.core.mongotemplate.find（mongotemplate。java:495)在org.springframework.data.mongodb.core.mongotemplate.find（mongotemplate。java:486)在com.snapdeal.com.timemachine.mao.timemachinemao.getvendorproductsforuploadid（timemachinemao。java:32)在com.snapdeal.coms.timemachine.service.timemachineservice.getvendorproductsforouploaddandsupc（timemachineservice。java:35)在com.snapdeal.com.timemachine.event.supcuploaddstateUpdateEventHandler.handleevent（supcuploaddstateUpdateEventHandler）。java:40)
我不知道为什么所有的线程都被阻塞了。我认为类只加载一次，以后不需要采取任何锁。