ERROR o.a.j.u.BeanShellInterpreter: Error invoking bsh method - Jmeter PreProcessor

Question

Need help figuring out an issue with Jmeter BeanShell PreProcessor, I am using below code to grab variable data and pass as next POST request but its failing, although I can see that all variables are being captured correctly.

Please help identify what is causing the issue

int keys = Integer.parseInt(vars.get("getkeys_matchNr"));
StringBuilder requestBuilder = new StringBuilder();
requestBuilder.append("[");
for (int i = 1; i <= keys; i++) {
    requestBuilder.append(vars.get("getkeys_" + i));
    if (i != keys) {
        requestBuilder.append(",");
    }
}
requestBuilder.append("]");
sampler.getArguments().getArgument(0).setValue(requestBuilder.toString());

getting below error:

2023-11-01 12:51:12,275 ERROR o.a.j.u.BeanShellInterpreter: Error invoking bsh method: eval Sourced file: inline evaluation of: ``int keys = Integer.parseInt(vars.get("getkeys_ . . . '' : Attempt to resolve method: toString() on undefined variable or class name: out

try setValue to different string - "sampler.getArguments().getArgument(0).setValue(out.toString(0));" but did not work either

Answer 1

I fail to see any declaration of out object in your code, most probably it's a copy-paste issue, try replacing out with requestBuilder and the issue will go away.

Also using Beanshell is a some form of a performance anti-pattern, since JMeter 3.1 you should be using JSR223 Test Elements and Groovy language for scripting.

Example code:

def requestBuilder = []
1.upto(vars.get('getkeys_matchNr') as int, { index ->
    requestBuilder.add(vars.get('getkeys_' + index))
})

def payload = new org.apache.jmeter.protocol.http.util.HTTPArgument('', new groovy.json.JsonBuilder(requestBuilder).toPrettyString(), '')
def arguments = sampler.getArguments()
arguments.addArgument(payload)
sampler.setArguments(arguments)

More information:

• Apache Groovy: Parsing and producing JSON
• Apache Groovy: What Is Groovy Used For?