When I use "LocalVariableTableParameterNameDiscoverer#getParameterNames" method to parse a SpEL expression, I found some objects blocked. The direct cause is the "LocalVariableTableParameterNameDiscoverer#getParameterNames" method called "ConcurrentHashMap#computeIfAbsent" method, and "ConcurrentHashMap#" in JDK8 has a "synchronized" on its table nodes. My JDK version is 8 and I don't know whether it is a problem. Here is the demo code:

public class SpelDemo {
    private static final LocalVariableTableParameterNameDiscorverer DISCOVERER = new LocalVariableTableParameterNameDiscoverer();

    public String doParseKey(String key, JoinPoint joinPoint) {
        Method method = ((MethodSignature) joinPoint.getSignature()).getMethod();
        String[] parameterNames = DISCOVERER.getParameterNames(method); // objects blocked here, waiting for synchronized
        // do something...
    }
}

Can the "getParameterNames" method check the key(the executing method) if absent or not before calling "LocalVariableTableParameterNameDiscoverer#getParameterNames"? Or I have a problem with my usage?

Comment From: a544793138

MethodSignature can getParameterNames

Comment From: sdeleuze

LocalVariableTableParameterNameDiscoverer has been deprecated in Spring Framework 6 as we recommend using StandardReflectionParameterNameDiscoverer with Java compilation using -parameters instead. Could you check if that's relevant for your use case?

Comment From: spring-projects-issues

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Comment From: zzzhangyxi

Ok. The problem caused by ConcurrentHashMap in jdk8. When using higher jdk version, like jdk 17 in spring 6, I think it will no longer be a problem. I will check it again later. Thank you very much for replying me.

---Original--- From: "Sébastien @.> Date: Thu, Jan 5, 2023 19:03 PM To: @.>; Cc: @.**@.**>; Subject: Re: [spring-projects/spring-framework] Causes performance issues whenparsing Spel using LocalVariableTableParameterNameDiscoverer (Issue #29244)

LocalVariableTableParameterNameDiscoverer has been deprecated in Spring Framework 6 as we recommend using StandardReflectionParameterNameDiscoverer with Java compilation using -parameters instead. Could you check if that's relevant for your use case?

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Comment From: spring-projects-issues

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Comment From: spring-projects-issues

Closing due to lack of requested feedback. If you would like us to look at this issue, please provide the requested information and we will re-open the issue.