现象
生产环境再一次发布后，突然大量告警，经过排查，发现出现大量接口报以下异常
{"timestamp":1750703779072,"status":500,"error":"Internal Server Error","exception":"java.lang.NoClassDefFoundError","message":"Could not initialize class java.sql.SQLException","path":"/xxx/xxx"}
系统日志
java.lang.NoClassDefFoundError: Could not initialize class java.sql.SQLException
at com.alibaba.druid.pool.DruidPooledConnection.checkStateInternal(DruidPooledConnection.java:1157)
at com.alibaba.druid.pool.DruidPooledConnection.checkState(DruidPooledConnection.java:1148)
at com.alibaba.druid.pool.DruidPooledConnection.prepareStatement(DruidPooledConnection.java:336)
at org.apache.ibatis.executor.statement.PreparedStatementHandler.instantiateStatement(PreparedStatementHandler.java:87)
at org.apache.ibatis.executor.statement.BaseStatementHandler.prepare(BaseStatementHandler.java:88)
at org.apache.ibatis.executor.statement.RoutingStatementHandler.prepare(RoutingStatementHandler.java:59)
at org.apache.ibatis.executor.SimpleExecutor.prepareStatement(SimpleExecutor.java:85)
at org.apache.ibatis.executor.SimpleExecutor.doQuery(SimpleExecutor.java:62)
at org.apache.ibatis.executor.BaseExecutor.queryFromDatabase(BaseExecutor.java:324)
at org.apache.ibatis.executor.BaseExecutor.query(BaseExecutor.java:156)
at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:109)
at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:83)
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:148)
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:141)
at sun.reflect.GeneratedMethodAccessor270.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:434)
at com.sun.proxy.$Proxy150.selectList(Unknown Source)
at org.mybatis.spring.SqlSessionTemplate.selectList(SqlSessionTemplate.java:231)
at org.apache.ibatis.binding.MapperMethod.executeForMany(MapperMethod.java:137)
at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:75)
at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:53)
at com.sun.proxy.$Proxy309.queryList(Unknown Source)
at com.custom.hsi.mm.uniondb.service.impl.IUnionCommonServiceImpl.getList(IUnionCommonServiceImpl.java:278)
at com.custom.hsi.mm.uniondb.service.impl.IUnionCommonServiceImpl.getEntity(IUnionCommonServiceImpl.java:206)
at com.alibaba.dubbo.common.bytecode.Wrapper116.invokeMethod(Wrapper116.java)
at com.alibaba.dubbo.rpc.proxy.javassist.JavassistProxyFactory$1.doInvoke(JavassistProxyFactory.java:47)
at com.alibaba.dubbo.rpc.proxy.AbstractProxyInvoker.invoke(AbstractProxyInvoker.java:76)
at com.alibaba.dubbo.config.invoker.DelegateProviderMetaDataInvoker.invoke(DelegateProviderMetaDataInvoker.java:52)
at com.alibaba.dubbo.rpc.protocol.InvokerWrapper.invoke(InvokerWrapper.java:56)
at com.alibaba.dubbo.rpc.filter.ExceptionFilter.invoke(ExceptionFilter.java:62)
at com.alibaba.dubbo.rpc.protocol.ProtocolFilterWrapper$1.invoke(ProtocolFilterWrapper.java:72)
at com.alibaba.dubbo.monitor.support.MonitorFilter.invoke(MonitorFilter.java:75)
at com.alibaba.dubbo.rpc.protocol.ProtocolFilterWrapper$1.invoke(ProtocolFilterWrapper.java:72)
at com.alibaba.dubbo.rpc.filter.TimeoutFilter.invoke(TimeoutFilter.java:42)
at com.alibaba.dubbo.rpc.protocol.ProtocolFilterWrapper$1.invoke(ProtocolFilterWrapper.java:72)
at com.alibaba.dubbo.rpc.protocol.dubbo.filter.TraceFilter.invoke(TraceFilter.java:78)
at com.alibaba.dubbo.rpc.protocol.ProtocolFilterWrapper$1.invoke(ProtocolFilterWrapper.java:72)
at com.alibaba.dubbo.rpc.filter.ContextFilter.invoke(ContextFilter.java:72)
at com.alibaba.dubbo.rpc.protocol.ProtocolFilterWrapper$1.invoke(ProtocolFilterWrapper.java:72)
at com.alibaba.dubbo.rpc.filter.GenericFilter.invoke(GenericFilter.java:131)
at com.alibaba.dubbo.rpc.protocol.ProtocolFilterWrapper$1.invoke(ProtocolFilterWrapper.java:72)
at com.alibaba.dubbo.rpc.filter.ClassLoaderFilter.invoke(ClassLoaderFilter.java:38)
at com.alibaba.dubbo.rpc.protocol.ProtocolFilterWrapper$1.invoke(ProtocolFilterWrapper.java:72)
at com.alibaba.dubbo.rpc.filter.EchoFilter.invoke(EchoFilter.java:38)
at com.alibaba.dubbo.rpc.protocol.ProtocolFilterWrapper$1.invoke(ProtocolFilterWrapper.java:72)
at com.alibaba.dubbo.rpc.protocol.dubbo.DubboProtocol$1.reply(DubboProtocol.java:103)
at com.alibaba.dubbo.remoting.exchange.support.header.HeaderExchangeHandler.handleRequest(HeaderExchangeHandler.java:96)
at com.alibaba.dubbo.remoting.exchange.support.header.HeaderExchangeHandler.received(HeaderExchangeHandler.java:172)
at com.alibaba.dubbo.remoting.transport.DecodeHandler.received(DecodeHandler.java:51)
at com.alibaba.dubbo.remoting.transport.dispatcher.ChannelEventRunnable.run(ChannelEventRunnable.java:80)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:750)
NoClassDefFoundError
这个日志让人摸不到头脑，jdk自己的类也会加载不到？这个肯定不是最终原因。接着往前找异常日志，结果发现。有堆栈溢出。
java.lang.StackOverflowError: null
at java.util.concurrent.atomic.AtomicReferenceFieldUpdater.newUpdater(AtomicReferenceFieldUpdater.java:110)
at java.sql.SQLException.<clinit>(SQLException.java:372)
at com.alibaba.druid.pool.DruidDataSource.handleConnectionException(DruidDataSource.java:1543)
at com.alibaba.druid.pool.DruidPooledConnection.handleException(DruidPooledConnection.java:133)
at com.alibaba.druid.pool.DruidPooledStatement.checkException(DruidPooledStatement.java:77)
at com.alibaba.druid.pool.DruidPooledPreparedStatement.execute(DruidPooledPreparedStatement.java:502)
at org.apache.ibatis.executor.statement.PreparedStatementHandler.query(PreparedStatementHandler.java:63)
at org.apache.ibatis.executor.statement.RoutingStatementHandler.query(RoutingStatementHandler.java:79)
at org.apache.ibatis.executor.SimpleExecutor.doQuery(SimpleExecutor.java:63)
at org.apache.ibatis.executor.BaseExecutor.queryFromDatabase(BaseExecutor.java:324)
at org.apache.ibatis.executor.BaseExecutor.query(BaseExecutor.java:156)
at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:109)
at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:83)
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:148)
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:141)
at sun.reflect.GeneratedMethodAccessor276.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:434)
at com.sun.proxy.$Proxy150.selectList(Unknown Source)
at org.mybatis.spring.SqlSessionTemplate.selectList(SqlSessionTemplate.java:231)
at org.apache.ibatis.binding.MapperMethod.executeForMany(MapperMethod.java:137)
at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:75)
at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:53)
at com.sun.proxy.$Proxy169.getCardInfo(Unknown Source)
at com.custom.hsi.mm.masterdb.service.impl.IMasterServiceImpl.getCardInfo(IMasterServiceImpl.java:1658)
at com.custom.hsi.mm.masterdb.service.impl.IMasterServiceImpl.getCardInfo(IMasterServiceImpl.java:1668)
at com.custom.hsi.mm.masterdb.service.impl.IMasterServiceImpl.getCardInfo(IMasterServiceImpl.java:1668)
at com.custom.hsi.mm.masterdb.service.impl.IMasterServiceImpl.getCardInfo(IMasterServiceImpl.java:1668)
at com.custom.hsi.mm.masterdb.service.impl.IMasterServiceImpl.getCardInfo(IMasterServiceImpl.java:1668)
at com.custom.hsi.mm.masterdb.service.impl.IMasterServiceImpl.getCardInfo(IMasterServiceImpl.java:1668)
...后续都是这个类
分析后，发现出问题的位置是，SQLException.java 中的静态属性初始化报错
编辑
但是这里报错为啥会影响后面所有的正常请求呢。
核心根因
因为 JVM 的类加载器有“懒加载”机制，只加载一次，失败后也不会重试。
即使你后来修复了递归调用，但如果你不重启 JVM，该类依然处于“初始化失败”状态。
某个请求触发了 SQLException 的构造
构造时由于线程栈已满，导致初始化失败
后续所有请求，哪怕没有异常，只要用了 SQLException，就会失败
从这一刻起：
| 使用方式 | 是否受影响 |
| new SQLException(...) | ❌ 报错：NoClassDefFoundError |
| catch (SQLException e) | ❌ 报错：NoClassDefFoundError |
| throws SQLException | ❌ 方法签名中声明也受影响 |
| Class.forName("java.sql.SQLException") | ❌ 同样报错 |
也就是说，只要你在代码中使用了 SQLException 这个类名，不管是不是真的抛出异常，都会失败。
示例说明
来看一段完整示例：
import com.alibaba.fastjson.JSONObject;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Proxy;
import java.sql.SQLException;
public class SQLExceptionSimulator {
public static void main(String[] args) {
try {
new Test();
} catch (Exception e) {
e.printStackTrace();
} catch (Throwable e) {
e.printStackTrace();
}
try {
Test2.x = false;
new Test();
} catch (Exception e) {
e.printStackTrace();
}
}
private static class Test2{
private static Boolean x = true;
static Boolean get() {
return x;
}
}
private static class Test{
Test() {
}
static {
if (Test2.get()) {
throw new RuntimeException("");
}
}
}
}
如果第一次 new Test() 时因为异常失败了：
那么第二次 new Test(); 也会失败：
编辑
