JRuby evalScript does not accept non-ascii characters. Is this the way it should be?

JRuby evalScriptLet vs. executeScript

package ruby.experiments;

import java.util.ArrayList;

import org.jruby.Ruby;
import org.jruby.javasupport.JavaEmbedUtils;

public class EvalScriptlet {

    public static void main(String[] args) {
        Ruby ruby = JavaEmbedUtils.initialize(new ArrayList<String>());
        String script = "puts 'Hello World'";
        ruby.executeScript(script, "<script>");
        ruby.evalScriptlet(script);
        String scriptUTF8 = "puts \"Árbol de demostración\"" ;
        ruby.executeScript(scriptUTF8, "<script>");
        ruby.evalScriptlet(scriptUTF8);
    }
}