Jmeter: BeanshellAssertion Error: Method Not Found In Class - class

Question

I simply want to read response from jdbc sampler and use it in an http request.
I created a BeanShellAssertion Script under a jdbc request and wrote just the below code, nothing else.
if(vars.getObjects("jdbcresult1").size!=0)
{
String jdbcresult1=vars.getObjects("jdbcresult1").get(0).get("jdbctrackingnumber1")+"";
vars.put("trackingnumber1",jdbcresult1);
log.info("TrackingNumber1 is: "+trackingnumber1);
}
Error:
2020-08-13 23:32:47,030 ERROR o.a.j.u.BeanShellInterpreter: Error
invoking bsh method: eval Sourced file: inline evaluation of: ``import
java.lang.Object; if(vars.getObjects("jdbcresult1").size!=0) {
String . . . '' : Error in method invocation: Method getObjects(
java.lang.String ) not found in
class'org.apache.jmeter.threads.JMeterVariables'
2020-08-13 23:32:47,030 WARN o.a.j.a.BeanShellAssertion: Error in
BeanShellAssertion
Question1: How do you decide what should you use to write a code to read jdbcresponse value:
a. beanshellassertion
b. beanshellpostprocessor
c. beanshelllistener
Question2: Solution to the original problem, to resolve the error ?

Answer 1

The problem is that:
vars.getObjects(...)
does not exist.
It should be :
vars.getObject(...)
See:
https://jmeter.apache.org/api/org/apache/jmeter/threads/JMeterVariables.html
Also it’s better to use JSR223 Assertion:
https://jmeter.apache.org/usermanual/component_reference.html#JSR223_Assertion