"Questions abour RM DBScan arff in java source"

Hi guys, I'm a Weka User trying to learn how to use rapidminer clustering algorithms in a simple application java.

I want to do a simple process that reads a arff file and use the DBScan. After that, show the results in the console of netbeans.

My code:

package rapidminer;

import com.rapidminer.Process;
import com.rapidminer.RapidMiner;
import com.rapidminer.RapidMiner.ExecutionMode;
import com.rapidminer.operator.Operator;
import com.rapidminer.operator.OperatorCreationException;
import com.rapidminer.operator.OperatorException;
import com.rapidminer.operator.clustering.clusterer.DBScan;
import com.rapidminer.operator.io.ArffExampleSource;
import com.rapidminer.operator.ports.PortException;
import com.rapidminer.tools.OperatorService;


public class Rapidminer 
{

    
    public static Process createProcess() {
	try 
        {
            // invoke init before using the OperatorService
            RapidMiner.setExecutionMode(ExecutionMode.COMMAND_LINE);
	    RapidMiner.init();
	} 
        catch (Exception e) 
        { 
            e.printStackTrace(System.out); 
        }

	// create process
	Process process = new Process();
	try 
        {
	    // create operator
	    Operator inputData = OperatorService.createOperator(ArffExampleSource.class);    
	    // set parameters
	    inputData.setParameter("data_file", "C:/iris.arff");
            
            // Clustering 
            Operator scan = OperatorService.createOperator(DBScan.class);
            scan.setParameter("min_points", Double.toString(5));
            scan.setParameter("epsilon", Double.toString(0.1));
            	     
	    // add operator to process
	    process.getRootOperator().getSubprocess(0).addOperator(inputData);
            process.getRootOperator().getSubprocess(0).addOperator(scan);

            inputData.getOutputPorts().getPortByName("output").connectTo(scan.getInputPorts().getPortByName("training set"));
           

	 } 
         catch (OperatorCreationException | PortException e) 
         { 
             e.printStackTrace(System.out); 
         }
	return process;
    }

    
    public static void main(String[] argv) 
    {
	// create process
	Process process = createProcess();
	// print process setup
	System.out.println(process.getRootOperator().createProcessTree(0));

	try 
        {
	    // perform process
	    process.run();

	} 
        catch (OperatorException e) 
        { 
            e.printStackTrace(System.out); 
        }
    }
}

Well, that's my questions:

1. How can I print the dbscan output in netbeans console?

2  When I executed the code, this error message was showed:

com.rapidminer.operator.UserError: No data was delivered at port Clustering.example set (disconnected). 
	at com.rapidminer.operator.ports.impl.AbstractPort.getData(AbstractPort.java:99)
	at com.rapidminer.operator.clustering.clusterer.AbstractClusterer.doWork(AbstractClusterer.java:94)
	at com.rapidminer.operator.Operator.execute(Operator.java:855)
	at com.rapidminer.operator.execution.SimpleUnitExecutor.execute(SimpleUnitExecutor.java:51)
	at com.rapidminer.operator.ExecutionUnit.execute(ExecutionUnit.java:711)
	at com.rapidminer.operator.OperatorChain.doWork(OperatorChain.java:379)
	at com.rapidminer.operator.Operator.execute(Operator.java:855)
	at com.rapidminer.Process.run(Process.java:949)
	at com.rapidminer.Process.run(Process.java:873)
	at com.rapidminer.Process.run(Process.java:832)
	at com.rapidminer.Process.run(Process.java:827)
	at com.rapidminer.Process.run(Process.java:817)
	at rapidminer.Rapidminer.main(Rapidminer.java:75)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:601)
	at com.javafx.main.Main.launchApp(Main.java:658)
	at com.javafx.main.Main.main(Main.java:805)

Well, that's newbie questions, but that's my doubts.  ;D