Convert a List to a Set (ArrayList to HashSet)

This example shows how to convert from an ArrayList to a HashSet. Since most Collection objects have a constructor that allows for passing in another Collection object we are able to make these kinds of conversions easily.
In the example we create an ArrayList to which we add a few string items. Next we create a HashSet and provide the reference to the ArrayList as argument to the HashSet constructor.
Finally we just loop through the HashSet and print out the contents.

import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

/**
*
* @author javadb.com
*/
public class Main {

    /**
     * Conversion from a List to a Set,
     * or from an ArrayList to a HashSet object
     */
    public void convertFromListToSet() {

    List fruitsList = new ArrayList ();
        fruitsList.add("Apples");
        fruitsList.add("Bananas");
        fruitsList.add("Oranges");
        fruitsList.add("Grapes");

        Set fruitsSet = new HashSet(fruitsList);

        for (Object theFruit : fruitsSet)
            System.out.println(theFruit);

    }

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        new Main().convertFromListToSet();
    }
}

The output from the code is not surprisingly the items in the same order as added to the ArrayList:

Apples
Bananas
Oranges
Grapes

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