java与matlab混合编程

com.mathworks.toolbox.javabuilder.MWNumericArray cannot be cast to java.lang.Double

@RestController
public class WcController {
    @RequestMapping("/getWc")
    public double getWc() throws MWException {
        WcFunction wcFunction = new WcFunction();
        Object[] a=wcFunction.Wcsolution(1,400.00);
        double b= (double) a[0];
        return b;
    }