How to close an android application?

There are many question regarding this topic but there is no clear answer. Although android's memory management is very solid, so many people believe that we shouldn't kill android application. My case is different. I want an option to close an application. I found following code for closing application but sometimes it doesn't work.It seems application just refreshing itself when i hit exit button on my application.

MainActivity.java

@Override
    public void onDestroy()
    {
        super.onDestroy();
        /*
         * Notify the system to finalize and collect all objects of the
         * application on exit so that the process running the application can
         * be killed by the system without causing issues. NOTE: If this is set
         * to true then the process will not be killed until all of its threads
         * have closed.
         */
        System.runFinalizersOnExit(true);

        /*
        * Force the system to close the application down completely instead of
        * retaining it in the background. The process that runs the application
        * will be killed. The application will be completely created as a new
        * application in a new process if the user starts the application
        * again.
        */
        System.exit(0);
    }

@Override
public boolean onMenuItemSelected(int featureId, MenuItem item) {
switch(item.getItemId()) {
   case R.id.close:
                Intent intentFinish = new Intent(this, FinishActivity.class).setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                startActivity(intentFinish);
                finish();
                return true;
}
return super.onMenuItemSelected(featureId, item);
}

FinishActivity.java

package com.mypackage;

import android.app.Activity;
import android.os.Bundle;

public class FinishActivity extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        finish();
    }
}

I also tried Process.killProcess(Process.myPid()); but it doesn't work.

I found my solution. Use this to close an application

Intent homeIntent = new Intent(Intent.ACTION_MAIN);
homeIntent.addCategory( Intent.CATEGORY_HOME );
homeIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(homeIntent);