[CAMEL-20802] Velocity shows error when using ${headers}

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Cannot Reproduce
• Affects Version/s: 4.6.0
• Component/s: camel-velocity
• Estimated Complexity: Unknown
• Assignee: Unassigned
• Reporter: Raymond
• Created: 24/May/24 14:53
• Updated: 31/May/24 10:49
• Resolved: 31/May/24 08:33

Description

In Camel 3 (3.20.8) I have the following route:

<route id="myRoute">
        <from uri="direct:in"/>
        <setHeader headerName="CamelVelocityTemplate">
            <simple>${headers}</simple>
        </setHeader>
        <to uri="velocity:generate"/>
        <to uri="log:foo//?skipBodyLineSeparator=false&amp;multiline=true&amp;showHeaders=false&amp;showBody=true&amp;showBodyType=true&amp;showFiles=true&amp;showException=false&amp;showStackTrace=false&amp;showCaughtException=false"/>
    </route>     

Then I get an output like this:

{Accept=text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7, Accept-Encoding=gzip, deflate, br, zstd, Accept-Language=nl-NL,nl;q=0.9,en-US;q=0.8,en;q=0.7, breadcrumbId=7FE304808A5EF7B-0000000000008538, CamelServletContextPath=/regressiontests/Velocity, CamelVelocityTemplate=(this Map), ComponentInitTime=1716561470224, Connection=close, Cookie=_ga=GA1.1.1085399545.1665049218; _ga_J0TKN8HXSY=GS1.1.1715979059.148.0.1715979059.0.0.0; nPT0%3D--35c503a9ecbf1d3922b78a7289ee8eb8f80e1d36, Host=assimbly-test:9001, sec-ch-ua="Google Chrome";v="125", "Chromium";v="125", "Not.A/Brand";v="24", sec-ch-ua-mobile=?0, sec-ch-ua-platform="Windows", Sec-Fetch-Dest=document, Sec-Fetch-Mode=navigate, Sec-Fetch-Site=none, Sec-Fetch-User=?1, Upgrade-Insecure-Requests=1, User-Agent=Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/125.0.0.0 Safari/537.36} 

However when running the route with Camel 4 (using 4.6.0 on JDK21) I get the following error:

java.lang.StackOverflowError: null
        at java.base/java.lang.AbstractStringBuilder.append(AbstractStringBuilder.java:806)
        at java.base/java.lang.StringBuffer.append(StringBuffer.java:425)
        at java.base/java.io.StringWriter.write(StringWriter.java:79)
        at org.apache.camel.util.json.Jsoner.serialize(Jsoner.java:963)
        at org.apache.camel.util.json.Jsoner.serialize(Jsoner.java:1004)
        at org.apache.camel.util.json.Jsoner.serialize(Jsoner.java:1006)