WildFly + Axis2 HTTP/2 Integration Guide

Tested on: WildFly 32 (OpenJDK 17, 21) and WildFly 39 (OpenJDK 21, 25). Configuration examples below use WildFly 32 syntax; WildFly 39 is compatible with the same configuration.

<!-- Minimal HTTP/2 Transport - Intelligent Defaults Handle Optimization -->
<transportSender name="http" class="org.apache.axis2.transport.h2.impl.httpclient5.H2TransportSender">
    <parameter name="PROTOCOL">HTTP/2.0</parameter>
</transportSender>

WildFly Server-Level HTTP/2 Configuration (RECOMMENDED)

<subsystem xmlns="urn:jboss:domain:undertow:14.0"
           default-virtual-host="default-host"
           default-servlet-container="default"
           default-server="default-server"
           statistics-enabled="${wildfly.undertow.statistics-enabled:${wildfly.statistics-enabled:false}}"
           default-security-domain="other">

    <!-- MINIMAL WILDFLY HTTP/2 - Optimized Buffer Pool Configuration -->
    <!-- Aligned with Enhanced Moshi H2 processing (64KB standard across all layers) -->
    <!-- Reduces buffer fragmentation and improves memory efficiency -->
    <byte-buffer-pool name="default" buffer-size="65536" max-pool-size="512" direct="true"/>

    <!-- Single-Layer Buffer Cache - Optimized for JSON Processing -->
    <!-- Aligned 64KB cache for consistent buffer management -->
    <buffer-cache name="default" buffer-size="65536" buffers-per-region="64"/>

    <server name="default-server">
        <!-- MINIMAL WILDFLY HTTP/2 - Optimized for Single-Layer Processing -->
        <!-- Reduced protocol overhead, optimized for Enhanced Moshi H2 JSON processing -->
        <http-listener name="default" socket-binding="http"
                       max-post-size="104857600"
                       redirect-socket="https"
                       enable-http2="true"
                       http2-enable-push="false"
                       http2-header-table-size="8192"
                       http2-initial-window-size="2097152"
                       http2-max-concurrent-streams="75"
                       http2-max-frame-size="65536"
                       http2-max-header-list-size="32768"
                       max-connections="150"
                       receive-buffer="4194304"
                       send-buffer="2097152"
                       no-request-timeout="300000"
                       request-parse-timeout="60000"
                       tcp-backlog="1024"/>

        <!-- MINIMAL WILDFLY HTTP/2 HTTPS - Aligned with HTTP configuration -->
        <!-- SSL-optimized single-layer HTTP/2 processing -->
        <https-listener name="https" socket-binding="https"
                        max-post-size="104857600"
                        ssl-context="applicationSSC"
                        enable-http2="true"
                        http2-enable-push="false"
                        http2-header-table-size="8192"
                        http2-initial-window-size="2097152"
                        http2-max-concurrent-streams="75"
                        http2-max-frame-size="65536"
                        http2-max-header-list-size="32768"
                        max-connections="150"
                        receive-buffer="4194304"
                        send-buffer="2097152"
                        no-request-timeout="300000"
                        request-parse-timeout="60000"
                        tcp-backlog="1024"/>

        <host name="default-host" alias="localhost">
            <!-- Enhanced Access Log for HTTP/2 Performance Monitoring -->
            <access-log pattern="%h %l %u %t "%r" %s %b "%{i,Referer}" "%{i,User-Agent}" Cookie: "%{i,COOKIE}" Set-Cookie: "%{o,SET-COOKIE}" SessionID: %S Thread: "%I" TimeTaken: %T Protocol: %H Bytes: %B"/>

            <!-- HTTP/2 Performance Optimization Filters -->
            <filter-ref name="gzip-compression"/>
            <filter-ref name="cache-control-headers"/>
        </host>
    </server>

    <!-- HTTP/2 Optimization Filters -->
    <filters>
        <!-- JSON compression for JSON-RPC / REST operations (30-50% reduction) -->
        <gzip name="gzip-compression"/>

        <!-- Cache Control Headers for Static Resources -->
        <response-header name="cache-control-headers"
                        header-name="Cache-Control"
                        header-value="public, max-age=2592000"/>
    </filters>

    <!-- MINIMAL WILDFLY HTTP/2 - Optimized Servlet Container -->
    <!-- Enhanced for single-layer HTTP/2 and JSON processing -->
    <servlet-container name="default" default-buffer-cache="default"
                       stack-trace-on-error="local-only"
                       default-encoding="UTF-8">
        <jsp-config development="false" mapped-file="false" check-interval="0"
                   x-powered-by="false" display-source-fragment="false"/>
        <websockets/>
        <session-cookie http-only="true" secure="true"/>
        <!-- Optimized session management for HTTP/2 multiplexing -->
        <persistent-sessions/>
    </servlet-container>
</subsystem>

<!-- WildFly 32 HTTP/2 Settings Optimized for Enhanced Moshi H2 -->
<!-- CORRECTED: Uses your existing ssl-context and matches buffer sizes -->

<!-- Buffer Pool Configuration (Aligned with HTTP/2 frame sizes) -->
<byte-buffer-pool name="default" buffer-size="32768" max-pool-size="1024" direct="true"/>
<buffer-cache name="default" buffer-size="32768"/>

<!-- HTTPS Listener with HTTP/2 Parameters -->
<https-listener name="https" socket-binding="https"
                ssl-context="applicationSSC"             <!-- CORRECTED: Matches your existing SSL context -->
                enable-http2="true"
                http2-enable-push="false"
                http2-header-table-size="4096"           <!-- Conservative headers -->
                http2-initial-window-size="2097152"      <!-- 2MB: avoids flow-control round trips -->
                http2-max-concurrent-streams="100"       <!-- Coordinated with transport-h2 -->
                http2-max-frame-size="32768"             <!-- ALIGNED: Matches buffer pool -->
                http2-max-header-list-size="16384"       <!-- Sufficient for JSON APIs -->
                max-connections="200"                     <!-- Matches your existing setup -->
                receive-buffer="2097152"                  <!-- Keep existing 2MB -->
                send-buffer="1048576"                     <!-- Keep existing 1MB -->
                no-request-timeout="300000"              <!-- 5min timeout for large payloads -->
                max-post-size="104857600"/>              <!-- 100MB max request size -->

Complete HTTP/2 + JSON Optimization Stack:
┌─────────────────────────────────────────────────────────────┐
│ 1. WildFly HTTP/2 (Server-Level)                           │
│    - HTTP/2 protocol negotiation and ALPN                  │
│    - Connection multiplexing and flow control              │
│    - TLS termination and header compression                │
└─────────────────────────────────────────────────────────────┘
                               │
┌─────────────────────────────────────────────────────────────┐
│ 2. transport-h2 Module (Axis2 HTTP/2 Transport)            │
│    - HTTP/2 client transport for outbound requests         │
│    - H2TransportSender with HTTP/2.0 protocol              │
│    - Stream management and async connection pooling        │
└─────────────────────────────────────────────────────────────┘
                               │
┌─────────────────────────────────────────────────────────────┐
│ 3. Enhanced Moshi H2 (JSON Processing)                     │
│    - JSON → OMElement conversion optimization              │
│    - Async processing for large payloads (1MB+)            │
│    - Field-specific parsing and memory management          │
└─────────────────────────────────────────────────────────────┘

<subsystem xmlns="urn:jboss:domain:undertow:14.0"
           default-virtual-host="default-host"
           default-servlet-container="default"
           default-server="default-server">

    <!-- CORRECTED: Aligned buffer pools for HTTP/2 optimization -->
    <byte-buffer-pool name="default" buffer-size="32768" max-pool-size="1024" direct="true"/>
    <buffer-cache name="default" buffer-size="32768"/>

    <server name="default-server">
        <!-- HTTP Connector with HTTP/2 support -->
        <http-listener name="default" socket-binding="http"
                       max-post-size="104857600"
                       redirect-socket="https"
                       enable-http2="true"
                       http2-enable-push="false"
                       http2-header-table-size="4096"
                       http2-initial-window-size="2097152"      <!-- 2MB: avoids flow-control round trips -->
                       http2-max-concurrent-streams="100"       <!-- Matches transport-h2 limit -->
                       http2-max-frame-size="32768"             <!-- ALIGNED: Matches buffer pool -->
                       http2-max-header-list-size="16384"
                       max-connections="200"
                       receive-buffer="2097152"
                       send-buffer="1048576"
                       no-request-timeout="300000"/>            <!-- 5min for large payloads -->

        <!-- HTTPS Connector (Production) -->
        <https-listener name="https" socket-binding="https"
                        max-post-size="104857600"
                        ssl-context="applicationSSC"             <!-- CORRECTED: Your actual SSL context -->
                        enable-http2="true"
                        http2-enable-push="false"
                        http2-header-table-size="4096"
                        http2-initial-window-size="2097152"      <!-- 2MB: avoids flow-control round trips -->
                        http2-max-concurrent-streams="100"       <!-- Matches transport-h2 limit -->
                        http2-max-frame-size="32768"             <!-- ALIGNED: Matches buffer pool -->
                        http2-max-header-list-size="16384"
                        max-connections="200"
                        receive-buffer="2097152"
                        send-buffer="1048576"
                        no-request-timeout="300000"/>            <!-- 5min for large payloads -->

        <host name="default-host" alias="localhost">
            <access-log pattern="%h %t "%r" %s %b %T Protocol:%H"/>
            <filter-ref name="gzip-compression"/>
        </host>
    </server>

    <filters>
        <gzip name="gzip-compression"/>
    </filters>

    <servlet-container name="default">
        <jsp-config development="false"/>
        <websockets/>
        <session-cookie http-only="true" secure="true"/>
    </servlet-container>
</subsystem>

<axisconfig name="AxisJava2.0-HTTP2-EnhancedMoshiH2-Complete">

    <!-- JSON processing is configured by selecting the message builder
         and formatter classes below — no additional threshold parameters
         are needed at the axis2.xml level. -->

    <!-- Enhanced JSON Message Builder -->
    <messageBuilder contentType="application/json"
                    class="org.apache.axis2.json.moshih2.EnhancedMoshiJsonBuilder"/>

    <!-- Enhanced JSON Message Formatter -->
    <messageFormatter contentType="application/json"
                      class="org.apache.axis2.json.moshih2.EnhancedMoshiJsonFormatter"/>

    <!-- HTTP/1.1 Transport (Fallback) -->
    <transportSender name="http"
                     class="org.apache.axis2.transport.http.impl.httpclient5.HTTPClient5TransportSender">
        <parameter name="PROTOCOL">HTTP/1.1</parameter>
    </transportSender>

    <!-- HTTP/2 Transport (Coordinated with WildFly + Moshi) -->
    <transportSender name="h2"
                     class="org.apache.axis2.transport.h2.impl.httpclient5.H2TransportSender">
        <parameter name="PROTOCOL">HTTP/2.0</parameter>

        <!-- Coordination with WildFly HTTP/2 -->
        <parameter name="maxConcurrentStreams">100</parameter>              <!-- Matches WildFly -->
        <parameter name="initialWindowSize">2097152</parameter>             <!-- 2MB: avoids flow-control round trips -->
        <parameter name="maxConnectionsTotal">50</parameter>
        <parameter name="maxConnectionsPerRoute">10</parameter>
        <parameter name="connectionTimeout">30000</parameter>
        <parameter name="responseTimeout">300000</parameter>                <!-- 5min matches WildFly -->

        <!-- JSON streaming is handled by the message formatter (e.g.
             MoshiStreamingMessageFormatter) — no additional transport sender
             parameters are needed for Moshi integration. -->
    </transportSender>

</axisconfig>

// Use HTTP/2 transport for outbound calls
ServiceClient client = new ServiceClient();
client.getOptions().setProperty(Constants.Configuration.TRANSPORT_NAME, "h2");
client.getOptions().setTo(new EndpointReference("https://api.example.com/service"));

// Streaming and async processing are handled automatically by the
// message formatter selected in axis2.xml. No client-side flags needed.

// Validate configuration alignment
curl -k --http2 --location 'https://localhost:8443/services/YourService' \
     --header 'Content-Type: application/json' \
     --data '{"largePayload": "..."}' \
     --trace-ascii trace.log

# Check for:
# - HTTP/2 protocol negotiation
# - Enhanced Moshi H2 async processing logs
# - Buffer alignment efficiency
# - No class loader conflicts

Troubleshooting

Common issues and resolution: