a class reflection sample in Java.

DryRunner.java

public class DryRunner extends RunnerBase {
  public DryRunner(String file) {
    super(file);
  }

  public Boolean delete()
  {
    log("dry:delete.");
    return true;
  }

  public Boolean doComplexThing(){
    log("dry:complex");
    return true;
  }
}

IRunner.java

public interface IRunner {
  public Boolean delete();
  public Boolean doComplexThing();
}

ReflectionSample.java

import java.lang.reflect.Constructor;

public class ReflectionSample {
  public static void main(String[] args) {
    run("huga", "DryRunner");
    run("hoge", "WetRunner");
  }

  // 簡便のため、String fileに変更している。runnerNameにクラス名を指定。
  public static void run(String file, String runnerName){
    // 引数の型を定義
    Class<? extends String> fileParam = String.class;

    try{
      Class<?> cls = Class.forName(runnerName);
      Constructor ct = cls.getConstructor(fileParam);
      RunnerBase runner = (RunnerBase)ct.newInstance(file);_

      runner.delete();
      runner.doComplexThing();
    } catch (Exception e) {
      e.printStackTrace();
    }
  }
}

RunnerBase.java

public class RunnerBase implements IRunner {
  protected String _file;

  public RunnerBase(String file) {
    _file = file;
  }

  public Boolean delete()
  {
    return false;
  }

  public Boolean doComplexThing(){
    return false;
  }

  protected void log(String str){
    System.out.println(str);
  }
}

WetRunner.java

public class WetRunner extends RunnerBase {
  public WetRunner(String file) {
    super(file);
  }

  public Boolean delete()
  {
    log("wet:delete.");
    return true;
  }

  public Boolean doComplexThing(){
    log("wet:complex");
    return true;
  }
}