Why does not tomcat throw an exception when server.start failed with a socket binding error.

[chickenlj]

Why does not tomcat throw an exception when server.start failed with a socket binding error.

https://github.com/apache/incubator-dubbo/blob/master/dubbo-remoting/dubbo-remoting-http/src/main/java/org/apache/dubbo/remoting/http/tomcat/TomcatHttpServer.java#L71

I do see the exception stack printed on the Console, whereas no exception was thrown in here:

try {
            tomcat.start();
        } catch (LifecycleException e) {
            throw new IllegalStateException("Failed to start tomcat server at " + url.getAddress(), e);
        } catch (Exception ee) {
            throw new IllegalStateException(e);
        }

This behavior will cause a tomcat based HTTP service being registered unexpectedly to the Registry even after the binding has failed.

@Override
    public <T> Exporter<T> export(final Invoker<T> originInvoker) throws RpcException {
         ... ...
        // socket binding exception extected
        final ExporterChangeableWrapper<T> exporter = doLocalExport(originInvoker, providerUrl);
        ... ... 
        // url to registry
        final Registry registry = getRegistry(originInvoker);
        register(registryUrl, registeredProviderUrl);
         
        return new DestroyableExporter<>(exporter);
    }

[ralf0131]

Can you provide the error stack trace?

[chickenlj]

try {
                    connector.init();
                } catch (Exception var9) {
                    String message = sm.getString("standardService.connector.initFailed", new Object[]{connector});
                    log.error(message, var9);
                    if (Boolean.getBoolean("org.apache.catalina.startup.EXIT_ON_INIT_FAILURE")) {
                        throw new LifecycleException(message);
                    }
                }

Turns out that there's a if (Boolean.getBoolean("org.apache.catalina.startup.EXIT_ON_INIT_FAILURE")) check that will decide whether tomcat will throw the exception out. By default, the return value would be false because we haven't set the org.apache.catalina.startup.EXIT_ON_INIT_FAILURE value, so it just skipped the throw action.

[chickenlj]

Here's the stack trace:

INFO: Initializing ProtocolHandler ["http-bio-8080"]
Jan 15, 2019 5:29:14 PM org.apache.coyote.AbstractProtocol init
SEVERE: Failed to initialize end point associated with ProtocolHandler ["http-bio-8080"]
java.net.BindException: Address already in use (Bind failed) <null>:8080
	at org.apache.tomcat.util.net.JIoEndpoint.bind(JIoEndpoint.java:413)
	at org.apache.tomcat.util.net.AbstractEndpoint.init(AbstractEndpoint.java:728)
	at org.apache.coyote.AbstractProtocol.init(AbstractProtocol.java:452)
	at org.apache.coyote.http11.AbstractHttp11JsseProtocol.init(AbstractHttp11JsseProtocol.java:119)
	at org.apache.catalina.connector.Connector.initInternal(Connector.java:978)
	at org.apache.catalina.util.LifecycleBase.init(LifecycleBase.java:102)
	at org.apache.catalina.core.StandardService.initInternal(StandardService.java:560)
	at org.apache.catalina.util.LifecycleBase.init(LifecycleBase.java:102)
	at org.apache.catalina.core.StandardServer.initInternal(StandardServer.java:840)
	at org.apache.catalina.util.LifecycleBase.init(LifecycleBase.java:102)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:135)
	at org.apache.catalina.startup.Tomcat.start(Tomcat.java:372)
	at org.apache.dubbo.remoting.http.tomcat.TomcatHttpServer.<init>(TomcatHttpServer.java:71)
	at org.apache.dubbo.remoting.http.tomcat.TomcatHttpBinder.bind(TomcatHttpBinder.java:28)
	at org.apache.dubbo.remoting.http.HttpBinder$Adaptive.bind(HttpBinder$Adaptive.java)
	at org.apache.dubbo.rpc.protocol.http.HttpProtocol.doExport(HttpProtocol.java:80)
	at org.apache.dubbo.rpc.protocol.AbstractProxyProtocol.export(AbstractProxyProtocol.java:71)
	at org.apache.dubbo.rpc.protocol.ProtocolFilterWrapper.export(ProtocolFilterWrapper.java:108)
	at org.apache.dubbo.rpc.protocol.ProtocolListenerWrapper.export(ProtocolListenerWrapper.java:57)
	at org.apache.dubbo.qos.protocol.QosProtocolWrapper.export(QosProtocolWrapper.java:63)
	at org.apache.dubbo.rpc.Protocol$Adaptive.export(Protocol$Adaptive.java)
	at org.apache.dubbo.registry.integration.RegistryProtocol.doLocalExport(RegistryProtocol.java:221)
	at org.apache.dubbo.registry.integration.RegistryProtocol.export(RegistryProtocol.java:181)
	at org.apache.dubbo.rpc.protocol.ProtocolFilterWrapper.export(ProtocolFilterWrapper.java:106)
	at org.apache.dubbo.rpc.protocol.ProtocolListenerWrapper.export(ProtocolListenerWrapper.java:55)
	at org.apache.dubbo.qos.protocol.QosProtocolWrapper.export(QosProtocolWrapper.java:61)
	at org.apache.dubbo.rpc.Protocol$Adaptive.export(Protocol$Adaptive.java)
	at org.apache.dubbo.config.ServiceConfig.doExportUrlsFor1Protocol(ServiceConfig.java:553)
	at org.apache.dubbo.config.ServiceConfig.doExportUrls(ServiceConfig.java:402)
	at org.apache.dubbo.config.ServiceConfig.doExport(ServiceConfig.java:363)
	at org.apache.dubbo.config.ServiceConfig.export(ServiceConfig.java:345)
	at org.apache.dubbo.config.spring.ServiceBean.onApplicationEvent(ServiceBean.java:104)
	at org.apache.dubbo.config.spring.ServiceBean.onApplicationEvent(ServiceBean.java:55)
	at org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener(SimpleApplicationEventMulticaster.java:172)
	at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:165)
	at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:139)
	at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:393)
	at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:347)
	at org.springframework.context.support.AbstractApplicationContext.finishRefresh(AbstractApplicationContext.java:883)
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:546)
	at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:139)
	at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:93)
	at org.apache.dubbo.samples.http.HttpProvider.main(HttpProvider.java:31)
Caused by: java.net.BindException: Address already in use (Bind failed)
	at java.net.PlainSocketImpl.socketBind(Native Method)
	at java.net.AbstractPlainSocketImpl.bind(AbstractPlainSocketImpl.java:387)
	at java.net.ServerSocket.bind(ServerSocket.java:375)
	at java.net.ServerSocket.<init>(ServerSocket.java:237)
	at java.net.ServerSocket.<init>(ServerSocket.java:181)
	at org.apache.tomcat.util.net.DefaultServerSocketFactory.createSocket(DefaultServerSocketFactory.java:49)
	at org.apache.tomcat.util.net.JIoEndpoint.bind(JIoEndpoint.java:400)
	... 42 more

[ralf0131]

Yes, you need to set org.apache.catalina.startup.EXIT_ON_INIT_FAILURE to true in order to let Tomcat to fail during initialization.