Java factory pattern - load classes dynamically

Question

I have a lot of classes UNO,HAV,MAS,KOS I want to create a factory pattern.

 validator.load("UNO").validate();

I need dynamically load classes into validator class and return an instance.
(dynamically set name of the class and return an instance)
My problem is: how can I return the instance of a class, if I have incompatible types?

I don't know what to write in return type of method.

The main problem in the Validator CLASS.

public SegmentAbstract load(String str) {

AND

return SegmentAbsClass.forName(identify);

Main class

try{
   validator.load("UNO").validate();
}catch(Exception e){
   System.out.print("No class ");
}

Abstract Class (SegmentAbstract)

public abstract class SegmentAbstract {

  public abstract Boolean validate();
}

Class UNO

public class UNA extends SegmentAbstract{

  public Boolean validate() {
    System.out.print("UNO!!");
    return true;
  }

}

Class Validator

public class Validator {

  public SegmentAbstract load(String str) {
    String identify = str.substring(0, 3);
    try {

      return SegmentAbsClass.forName(identify);
    }
    catch(Exception e) {
      return this;
    }

  }
}

Answer 1

I will do something like that:

// ISegment.java
public interface ISegment {
    Boolean validate();
}

// Uno.java
public class Uno implements ISegment {
    public Boolean validate() {
        System.out.print("UNO!!");
        return true;
    }
}

// SegmentFactory.java
public final class SegmentFactory {
    public static enum Supported {
        UNO("uno", Uno.class), /* ... */, HAV("hav", Hav.class);

        private final Class<?> clazz;
        private final String name;

        private Supported(final String name, final Class<?> clazz) {
            this.name = name;
            this.clazz = clazz;
        }

        public Class<?> getClazz() {
            return clazz;
        }

        public static Supported for(final String name) {
            for (final Supported s : values()) {
                if (s.name.equals(name) {
                    return s;
                }
            }
            return null; // a default one
        }
    }

    public static ISegment create(final Supported supp) {
        if (supp == null) {
            return null;
        }
        return supp.getClazz.newInstance();
    }

    private SegmentFactory() {
        // avoid instantiation
    }
}

usage:

final ISegment sa = SegmentFactory.create(SegmentFactory.Supported.for("uno"));
sa.validate();

Not tested!!