I am creating a simple plug-in to generate Fibonacci series. In my java code I h

Did you see the successful installation message in the log after placing the JAR in the plugins folder? Looks like it failed to deploy.

As mentioned by Eduardo, the plugin deployment must have failed. In my experience, I have always encountered an error whenever I tried to return ArrayList. (The exact error is: Invalid Error: Unsupported Type: java.util.List...) You have to convert it back to an array. You could use the method .toArray() for converting the ArrayList to simple array, then return it.

@chetany what should i set my return type to then after using toArray()

@zianf, use Integer[] as the return type

my function appear in the expression rule. My java code for fibonacci series plugin is:

import java.util.ArrayList;

import org.apache.log4j.Logger;

import com.appiancorp.services.ServiceContext;
import com.appiancorp.suiteapi.expression.annotations.Function;
import com.appiancorp.suiteapi.expression.annotations.Parameter;
import com.appiancorp.suiteapi.type.AppianType;


@MathfunctionCategory
public class fibonacci {

          private static final Logger LOG = Logger.getLogger(fibonacci.class);

          @SuppressWarnings("deprecation")
          @Function(returnType=AppianType.ARRAY)
          public Integer[] fibonacci(ServiceContext sc, @Parameter(type=AppianType.INTEGER) int fibo) {
                    ArrayList<Integer> a = new ArrayList<Integer>();
                    int a0=0, a1=1;
                    a.add(a0);
                    a.add(a1);
                    int a2=0;
                    for(int i=2;i<fibo;i++)
                    {
                              a2=a0+a1;
                              a.add(a2);
                              a0=a1;
                              a1=a2;
                    }
                    
                    return (Integer[]) a.toArray();
          }

}

I get the error:

Expression evaluation error : Unresolved compilation problem: Type mismatch: cannot convert from Object[] to Integer[]

@zianf, in the return statement, use: return a.toArray(new Integer[a.size()]); No need to cast. Also, the returnType in @Function annotation is not necessary. It is deprecated.

ok also I tried one more thing and it worked for me. The ArrayList Object 'a' I converted into String i.e a.toString and stored this value in a variable and eventually returned that variable. My return type then changed to String

I am not sure why you reply to a 6 years old post, but find the documentation here:

docs.appian.com/.../extending-appian.html