java.util.ConcurrentModificationException when iterating over ((SOAPMessageContext) mc).getMessage().getMimeHeaders().getAllHeaders()

Question

I have a

public class LoggingHandler implements SOAPHandler<SOAPMessageContext> {

and in the

public boolean handleMessage(SOAPMessageContext context)

I have the below processing of the message headers

            LOGGER.trace("Starting processing msg in try block");
            SOAPMessage msg = ((SOAPMessageContext) mc).getMessage();
            LOGGER.trace("Cast message and getting message");
            MimeHeaders mimeHeaders = msg.getMimeHeaders();
            LOGGER.trace("Getting headers");
            Iterator mhIterator = mimeHeaders.getAllHeaders();
            LOGGER.trace("Starting file creation for user {}", user); //not actually affecting the SOAP message, but needed according to my business logic
            msg.writeTo(baos);
            FileWriter fw = new FileWriter(filename, true);
            BufferedWriter bw = new BufferedWriter(fw);
            PrintWriter out = new PrintWriter(bw);
            LOGGER.trace("File opened for filename {}", filename);
            LOGGER.trace(type);
            //out.println(type);
            //out.flush();
            while (mhIterator.hasNext()) {
                LOGGER.trace("Iterator loop started");
                MimeHeader mh = (MimeHeader) mhIterator.next();
                LOGGER.trace("Iterator next requested");
                String header = mh.getName() + " : " + mh.getValue();
                LOGGER.trace("Iterator MimeHeared values taken");
                LOGGER.trace(header);
                out.print(formattedDateTime+Thread.currentThread().getId()+" "+(outboundProperty?"Request":"Response")+" "+user+" "+header+"\r\n");
                out.flush();
            }

So,

LOGGER.trace("Iterator loop started");

works, but

MimeHeader mh = (MimeHeader) mhIterator.next();

already hangs and fails with below exception. For me it isn't clear, as I don't touch the data being iterated.

2022-10-26 19:25:48.595 [http-nio-127.0.0.1-8080-exec-6] ERROR c.o.s.w.s.i.WebServiceExceptionHandler - java.util.ConcurrentModificationException
javax.xml.ws.WebServiceException: java.util.ConcurrentModificationException
        at com.sun.xml.ws.handler.ClientSOAPHandlerTube.callHandlersOnRequest(ClientSOAPHandlerTube.java:120)
        at com.sun.xml.ws.handler.HandlerTube.processRequest(HandlerTube.java:97)
        at com.sun.xml.ws.api.pipe.Fiber.__doRun(Fiber.java:1106)
        at com.sun.xml.ws.api.pipe.Fiber._doRun(Fiber.java:1020)
        at com.sun.xml.ws.api.pipe.Fiber.doRun(Fiber.java:989)
        at com.sun.xml.ws.api.pipe.Fiber.runSync(Fiber.java:847)
        at com.sun.xml.ws.client.Stub.process(Stub.java:433)
        at com.sun.xml.ws.client.sei.SEIStub.doProcess(SEIStub.java:161)
        at com.sun.xml.ws.client.sei.SyncMethodHandler.invoke(SyncMethodHandler.java:78)
        at com.sun.xml.ws.client.sei.SyncMethodHandler.invoke(SyncMethodHandler.java:62)
        at com.sun.xml.ws.client.sei.SEIStub.invoke(SEIStub.java:131)
        at com.sun.proxy.$Proxy543.getUserInfo(Unknown Source)
        at com.openpayment.client.basia.BankServiceClientImpl.getUserInfo(BankServiceClientImpl.java:47)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.base/java.lang.reflect.Method.invoke(Method.java:566)
        at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:333)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:190)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)
        at org.springframework.aop.framework.adapter.AfterReturningAdviceInterceptor.invoke(AfterReturningAdviceInterceptor.java:55)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:168)
        at org.springframework.aop.aspectj.MethodInvocationProceedingJoinPoint.proceed(MethodInvocationProceedingJoinPoint.java:96)
        at com.openpayment.client.basia.handler.error.LoggingFilterAspect.putToLogOn(LoggingFilterAspect.java:38)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.base/java.lang.reflect.Method.invoke(Method.java:566)
        at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethodWithGivenArgs(AbstractAspectJAdvice.java:627)
        at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethod(AbstractAspectJAdvice.java:616)
        at org.springframework.aop.aspectj.AspectJAroundAdvice.invoke(AspectJAroundAdvice.java:70)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:168)
        at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
        at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:213)
        at com.sun.proxy.$Proxy94.getUserInfo(Unknown Source)
        at com.openpayment.impl.service.AgentServiceImpl.createOrUpdateAgent(AgentServiceImpl.java:597)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.base/java.lang.reflect.Method.invoke(Method.java:566)
        at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:333)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:190)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)
        at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:99)
        at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:283)
        at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
        at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
        at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:213)
        at com.sun.proxy.$Proxy105.createOrUpdateAgent(Unknown Source)
        at com.openpayment.site.web.service.UserResource.createOrUpdateUser(UserResource.java:75)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.base/java.lang.reflect.Method.invoke(Method.java:566)
        at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205)
        at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:133)
        at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:97)
        at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:854)
        at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:765)
        at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
        at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:967)
        at com.openpayment.site.web.service.init.SiteWebDispatcherServlet.doDispatch(SiteWebDispatcherServlet.java:48)
        at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901)
        at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
        at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:872)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:681)
        at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:764)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:228)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:163)
        at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:190)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:163)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:317)
        at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:127)
        at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:91)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
        at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:114)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
        at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:137)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
        at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:111)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
        at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:170)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
        at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:63)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
        at org.springframework.security.oauth2.provider.authentication.OAuth2AuthenticationProcessingFilter.doFilter(OAuth2AuthenticationProcessingFilter.java:176)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
        at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:116)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
        at org.springframework.security.web.header.HeaderWriterFilter.doFilterInternal(HeaderWriterFilter.java:66)
        at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
        at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:105)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
        at org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:56)
        at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
        at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
        at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:214)
        at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:177)
        at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:347)
        at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:263)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:190)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:163)
        at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202)
        at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97)
        at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542)
        at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:143)
        at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
        at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:687)
        at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78)
        at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:357)
        at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:382)
        at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
        at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:893)
        at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1723)
        at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
        at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
        at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
        at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
        at java.base/java.lang.Thread.run(Thread.java:829)
Caused by: java.util.ConcurrentModificationException: null
        at java.base/java.util.Vector$Itr.checkForComodification(Vector.java:1321)
        at java.base/java.util.Vector$Itr.next(Vector.java:1277)
        at com.openpayment.client.basia.handler.LoggingHandler.logMessage(LoggingHandler.java:108)
        at com.openpayment.client.basia.handler.LoggingHandler.handleMessage(LoggingHandler.java:49)
        at com.openpayment.client.basia.handler.LoggingHandler.handleMessage(LoggingHandler.java:26)
        at com.sun.xml.ws.handler.HandlerProcessor.callHandleMessage(HandlerProcessor.java:267)
        at com.sun.xml.ws.handler.HandlerProcessor.callHandlersRequest(HandlerProcessor.java:108)
        at com.sun.xml.ws.handler.ClientSOAPHandlerTube.callHandlersOnRequest(ClientSOAPHandlerTube.java:112)
        ... 124 common frames omitted

By the end, the full class is given, the iterator causiong a problem is commented out:

package com.openpayment.client.basia.handler;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;

import javax.xml.bind.DatatypeConverter;
import javax.xml.namespace.QName;
import javax.xml.soap.MimeHeader;
import javax.xml.soap.MimeHeaders;
import javax.xml.soap.SOAPException;
import javax.xml.soap.SOAPMessage;
import javax.xml.ws.handler.MessageContext;
import javax.xml.ws.handler.soap.SOAPHandler;
import javax.xml.ws.handler.soap.SOAPMessageContext;
import java.io.*;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.util.Collections;
import java.util.Date;
import java.util.Iterator;
import java.util.Set;

public class LoggingHandler implements SOAPHandler<SOAPMessageContext> {
    private static final Logger LOGGER = LoggerFactory.getLogger(LoggingHandler.class);

    private String tempLogfilesLocation;

    private String user;
    private Boolean toLog;

    public LoggingHandler(String user, Boolean toLog, String tempLogfilesLocation) {
        this.user = user;
        this.toLog = toLog;
        this.tempLogfilesLocation = tempLogfilesLocation;
    }

    public void close(MessageContext context) {
    }

    public boolean handleFault(SOAPMessageContext context) {
        logMessage(context, "SOAP Error is : ");
        return true;
    }

    public boolean handleMessage(SOAPMessageContext context) {
        logMessage(context, "SOAP Message: ");
        return true;
    }

    public Set<QName> getHeaders() {
        return Collections.emptySet();
    }

    private boolean logMessage(MessageContext mc, String type) {
        // try {
        MessageDigest md = null;
        try {
            md = MessageDigest.getInstance("MD5");
        } catch (NoSuchAlgorithmException e) {
            throw new RuntimeException(e);
        }
        LOGGER.trace("Hanldler User {}", user);
        LOGGER.trace("Handler toLog {}", toLog);
        LOGGER.trace("Handler tempLogfilesLocation {}", tempLogfilesLocation);
        md.update(user.getBytes());
        LOGGER.trace("md updated");
        byte[] digest = md.digest();
        LOGGER.trace("digest calculated");
        String usernameHash = DatatypeConverter.printHexBinary(digest).toUpperCase();
        LOGGER.trace("userhashname {} of user {}", usernameHash, user);
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        LOGGER.trace("Outputstream created");
        String filename = tempLogfilesLocation + usernameHash + ".log";
        LOGGER.trace("Starting processing msg {}", mc.toString());
        if (toLog == null) {
            this.toLog = false;
        }
        LocalDateTime printDate = LocalDateTime.now();
        DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss.SSS ");
        String formattedDateTime = printDate.format(formatter); // "1986-04-08 12:30"

        Boolean outboundProperty = (Boolean) mc.get(MessageContext.MESSAGE_OUTBOUND_PROPERTY);

        if (toLog) { //if username is present for the SOAP query; it use to be present, so we rely on that!
            LOGGER.trace("Starting processing msg before try block");
            try {
                LOGGER.trace("Starting processing msg in try block");
                SOAPMessage msg = ((SOAPMessageContext) mc).getMessage();
                LOGGER.trace("Cast message and getting message");
                MimeHeaders mimeHeaders = msg.getMimeHeaders();
                LOGGER.trace("Getting headers");
                Iterator mhIterator = mimeHeaders.getAllHeaders();

                LOGGER.trace("Starting file creation for user {}", user);
                msg.writeTo(baos);
                FileWriter fw = new FileWriter(filename, true);
                BufferedWriter bw = new BufferedWriter(fw);
                PrintWriter out = new PrintWriter(bw);
                LOGGER.trace("File opened for filename {}", filename);
                LOGGER.trace(type);
                //out.println(type);
                //out.flush();
//                while (mhIterator.hasNext()) {
//                    LOGGER.trace("Iterator loop started");
//                    MimeHeader mh = (MimeHeader) mhIterator.next();
//                    LOGGER.trace("Iterator next requested");
//                    String header = mh.getName() + " : " + mh.getValue();
//                    LOGGER.trace("Iterator MimeHeared values taken");
//                    LOGGER.trace(header);
//                    out.print(formattedDateTime+Thread.currentThread().getId()+" "+(outboundProperty?"Request":"Response")+" "+user+" "+header+"\r\n");
//                    out.flush();
//                }
                LOGGER.trace(" " + simpleSecureFilter(baos.toString()));
                out.print(formattedDateTime+Thread.currentThread().getId()+" "+(outboundProperty?"Request":"Response")+" "+user+" "+simpleSecureFilter(baos.toString())+"\r\n");
                out.flush();
                out.close();
                baos.close();
                LOGGER.trace("SOAP Message has been written to the file {}", filename);

            } catch (IOException e) {
                LOGGER.error("Error logging SOAP message to file " + filename + " for user " + user, e);
            } catch (SOAPException e) {
                LOGGER.trace("Starting file creation for catching soap exceptions for user {}", user);
                FileWriter fw = null;
                try {
                    fw = new FileWriter(filename, true);
                    BufferedWriter bw = new BufferedWriter(fw);
                    PrintWriter out = new PrintWriter(bw);
                    out.println(e.getMessage());
                    LOGGER.error("Soap Exception", e);
                } catch (IOException ex) {
                    LOGGER.error("Exception when trying to write tio the file SOAP fault", ex);
                    throw new RuntimeException(ex);
                }
            }
        }
        else {
            LOGGER.trace("Else block for toLog {}", toLog);
        }
        LOGGER.trace("Call ended");

        return true;
    }

    private String simpleSecureFilter(String input) {
        String[] secureTags = new String[]{"password", "pNewPass"};
        for (String secureTag : secureTags) {
            int startIndex = input.indexOf(secureTag + ">");
            if (startIndex != -1) {
                int endIndex = input.substring(startIndex).indexOf("</");
                String password = input.substring(startIndex + secureTag.length() + 1, startIndex + endIndex);
                return input.replaceAll(secureTag + ">" + password + "</", secureTag + ">***</");
            }
        }
        return input;
    }
}

So which line is `LoggingHandler.java:108`? And what is happening around lines 26 and 49 of the same file? — John Bollinger, Oct 26 '22 at 13:40
49: logMessage(context, "SOAP Message: "); //actually this is called inside public boolean handleMessage(SOAPMessageContext context) to call the method there line 108 is located — Eljah, Oct 26 '22 at 13:47
just having a quick glance at the code: is it possible that both `handleMessage` and `handleFault` get called "at the same time" with the same instance of `SOAPMessageContext` ? — cyberbrain, Oct 26 '22 at 13:52
The code posted does not correspond to the stack trace presented. The stack trace shows a direct call at line LoggingHandler.java:26, in a method named `handleMessage()`, either recursively to the same `handleMessage()` method or to another method with that name, the latter of which encompasses line 49 of the file. One does not need to count lines to see that the code posted does not match. There is only one `handleMessage()` method, and it does not invoke itself recursively. — John Bollinger, Oct 26 '22 at 13:55
...Hmmm ...why has `SoapHandler` this extra `getHeaders()` method, and why do you return empty set from it? (Looks like you access the headers wrong/at a unfavorable moment.. and the existence of this method hints to it..) — xerx593, Oct 26 '22 at 14:10
@JohnBollinger that's also suspicious for me. But I have no clues why it is shown in the stacktrace twice. The line 26 points to the class definition — Eljah, Oct 26 '22 at 14:14
@cyberbrain I tried to debug that, but never faced those calls at the same time — Eljah, Oct 26 '22 at 14:15
..exactly...and for what?;) ..[javadoc-6](https://docs.oracle.com/javaee/6/api/index.html?javax/xml/ws/handler/soap/SOAPHandler.html):"Gets the header blocks that can be processed by this Handler instance." ..of course then still confusing, why "Iterator loop started" happens.. — xerx593, Oct 26 '22 at 14:18
That's not just suspicious, @IlyaYevlampiev, it should be *alarming*. At minimum, you should recognize that the most likely conclusion is that the version of `LoggingHandler` deployed in your application is not derived from the source code you're looking at. If that's the case, then no amount of debugging the code presented will lead you to a solution to the observed problem. — John Bollinger, Oct 26 '22 at 14:39
So due to the differences between stacktrace and code - are you sure this is the code that's actually running? (Even if it sounds stupid - happened to me before) Did you try to change the log message that works so you see the code changed? Does the debugger make sense when you set a breakpoint? Sometimes old code survives in web containers, so did you restart that? — cyberbrain, Oct 26 '22 at 14:40
Surely, the new deployments are reflected. I have added new trace lines and I see all of the updates. As for the stacktrace, why it can point to the class initialization line while showing it being executed within the specific method? — Eljah, Oct 26 '22 at 15:08

java.util.ConcurrentModificationException when iterating over ((SOAPMessageContext) mc).getMessage().getMimeHeaders().getAllHeaders()

0 Answers0