Stack trace printed even though SSLException is being handled

Question

I'm getting SSLHandshakeException when making requests through WebClient. Even though I am catching the exception succesfully (custom LOG4J log.error message is being displayed) the stack trace is printed on the console.

It is a reactive app with Spring WebFlux in Java, so the server is Netty. This is the exception I'm getting:

javax.net.ssl.SSLHandshakeException: The server selected protocol version TLS10 is not accepted by client preferences [TLS13, TLS12]

This is the method. You can see the error is being handled with onErrorResume. I'm getting the custom error message I set and the app keeps running, but the stack trace is being printed on the console anyway. This happens for SSLExceptions and variants of it. I've tried changing config for LOG4J, creating XML file, a Global Exception Handler and nothing works.

I'm afraid I cannot provide username and password.

public Mono\<Token\> getToken(String url, String sellerId) {

    return this.webClient.post()
            .uri(url)
            .contentType(MediaType.APPLICATION_FORM_URLENCODED)
            .accept(MediaType.APPLICATION_JSON)
            .body(BodyInserters.fromFormData("grant_type", "password")
                    .with("username", "XXX")
                    .with("password", "XXXXXX"))
            .retrieve()
            .bodyToMono(Token.class)
            .onErrorResume(e -> {
                log.error("Error getting token for Seller {}. URL {}: {}", sellerId, url, e.getMessage());
                return Mono.empty();
            });

}

I know a workaround for this would be to enable TLS 1.0, which is not recommended due to security vulnerabilities. I just want the stack trace to not be printed in the console. Maybe it has to do with some Netty or WebClient default configuration?

This is the stack trace:

2024-06-14T09:30:43.879-03:00 ERROR 7852 --- [ctor-http-nio-8] c.a.m.requester.Requester                : Error getting token for Seller poctokin0005. URL https://goodsweet.arcordis.com.ar:14551/api/token: The server selected protocol version TLS10 is not accepted by client preferences [TLS13, TLS12]
2024-06-14T09:30:43.879-03:00  WARN 7852 --- [ctor-http-nio-5] r.netty.http.client.HttpClientConnect    : [fd0dcf4a, L:/10.133.26.164:57760 - R:proxyintegraciones.arcorgroup.com/10.140.7.125:9090] The connection observed an error

javax.net.ssl.SSLHandshakeException: The server selected protocol version TLS10 is not accepted by client preferences [TLS13, TLS12]
    at java.base/sun.security.ssl.Alert.createSSLException(Alert.java:131) ~[na:na]
    at java.base/sun.security.ssl.Alert.createSSLException(Alert.java:117) ~[na:na]
    at java.base/sun.security.ssl.TransportContext.fatal(TransportContext.java:365) ~[na:na]
    at java.base/sun.security.ssl.TransportContext.fatal(TransportContext.java:321) ~[na:na]
    at java.base/sun.security.ssl.TransportContext.fatal(TransportContext.java:312) ~[na:na]
    at java.base/sun.security.ssl.ServerHello$ServerHelloConsumer.onServerHello(ServerHello.java:972) ~[na:na]
    at java.base/sun.security.ssl.ServerHello$ServerHelloConsumer.consume(ServerHello.java:894) ~[na:na]
    at java.base/sun.security.ssl.SSLHandshake.consume(SSLHandshake.java:396) ~[na:na]
    at java.base/sun.security.ssl.HandshakeContext.dispatch(HandshakeContext.java:480) ~[na:na]
    at java.base/sun.security.ssl.SSLEngineImpl$DelegatedTask$DelegatedAction.run(SSLEngineImpl.java:1277) ~[na:na]
    at java.base/sun.security.ssl.SSLEngineImpl$DelegatedTask$DelegatedAction.run(SSLEngineImpl.java:1264) ~[na:na]
    at java.base/java.security.AccessController.doPrivileged(AccessController.java:712) ~[na:na]
    at java.base/sun.security.ssl.SSLEngineImpl$DelegatedTask.run(SSLEngineImpl.java:1209) ~[na:na]
    at io.netty.handler.ssl.SslHandler.runDelegatedTasks(SslHandler.java:1651) ~[netty-handler-4.1.105.Final.jar:4.1.105.Final]
    at io.netty.handler.ssl.SslHandler.unwrap(SslHandler.java:1497) ~[netty-handler-4.1.105.Final.jar:4.1.105.Final]
    at io.netty.handler.ssl.SslHandler.decodeJdkCompatible(SslHandler.java:1338) ~[netty-handler-4.1.105.Final.jar:4.1.105.Final]
    at io.netty.handler.ssl.SslHandler.decode(SslHandler.java:1387) ~[netty-handler-4.1.105.Final.jar:4.1.105.Final]
    at io.netty.handler.codec.ByteToMessageDecoder.decodeRemovalReentryProtection(ByteToMessageDecoder.java:529) ~[netty-codec-4.1.105.Final.jar:4.1.105.Final]
    at io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:468) ~[netty-codec-4.1.105.Final.jar:4.1.105.Final]
    at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:290) ~[netty-codec-4.1.105.Final.jar:4.1.105.Final]
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:444) ~[netty-transport-4.1.105.Final.jar:4.1.105.Final]
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:420) ~[netty-transport-4.1.105.Final.jar:4.1.105.Final]
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:412) ~[netty-transport-4.1.105.Final.jar:4.1.105.Final]
    at io.netty.handler.proxy.ProxyHandler.channelRead(ProxyHandler.java:255) ~[netty-handler-proxy-4.1.105.Final.jar:4.1.105.Final]
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:442) ~[netty-transport-4.1.105.Final.jar:4.1.105.Final]
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:420) ~[netty-transport-4.1.105.Final.jar:4.1.105.Final]
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:412) ~[netty-transport-4.1.105.Final.jar:4.1.105.Final]
    at io.netty.channel.CombinedChannelDuplexHandler$DelegatingChannelHandlerContext.fireChannelRead(CombinedChannelDuplexHandler.java:436) ~[netty-transport-4.1.105.Final.jar:4.1.105.Final]
    at io.netty.channel.CombinedChannelDuplexHandler.channelRead(CombinedChannelDuplexHandler.java:253) ~[netty-transport-4.1.105.Final.jar:4.1.105.Final]
    at io.netty.handler.proxy.HttpProxyHandler$HttpClientCodecWrapper.channelRead(HttpProxyHandler.java:284) ~[netty-handler-proxy-4.1.105.Final.jar:4.1.105.Final]
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:444) ~[netty-transport-4.1.105.Final.jar:4.1.105.Final]
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:420) ~[netty-transport-4.1.105.Final.jar:4.1.105.Final]
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:412) ~[netty-transport-4.1.105.Final.jar:4.1.105.Final]
    at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410) ~[netty-transport-4.1.105.Final.jar:4.1.105.Final]
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:440) ~[netty-transport-4.1.105.Final.jar:4.1.105.Final]
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:420) ~[netty-transport-4.1.105.Final.jar:4.1.105.Final]
    at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919) ~[netty-transport-4.1.105.Final.jar:4.1.105.Final]
    at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:166) ~[netty-transport-4.1.105.Final.jar:4.1.105.Final]
    at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:788) ~[netty-transport-4.1.105.Final.jar:4.1.105.Final]
    at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:724) ~[netty-transport-4.1.105.Final.jar:4.1.105.Final]
    at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:650) ~[netty-transport-4.1.105.Final.jar:4.1.105.Final]
    at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:562) ~[netty-transport-4.1.105.Final.jar:4.1.105.Final]
    at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:997) ~[netty-common-4.1.105.Final.jar:4.1.105.Final]
    at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74) ~[netty-common-4.1.105.Final.jar:4.1.105.Final]
    at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30) ~[netty-common-4.1.105.Final.jar:4.1.105.Final]
    at java.base/java.lang.Thread.run(Thread.java:842) ~[na:na]Final.jar:4.1.105.Final]