jmeter测试下载的时候一直报错，请问这是为啥

2021-11-15 16:07:20,750 ERROR o.a.j.u.BeanShellInterpreter: Error invoking bsh method: eval Sourced file: inline evaluation of: import java.io.*; byte[] result = prev.getResponseData(); //String file_name = . . . '' : Typed variable declaration : Object constructor 2021-11-15 16:07:20,750 WARN o.a.j.p.j.s.BeanShellSampler: Exception executing script. org.apache.jorphan.util.JMeterException: Error invoking bsh method: eval Sourced file: inline evaluation of:import java.io.*; byte[] result = prev.getResponseData(); //String file_name = . . . '' : Typed variable declaration : Object constructor