How can i use a for each loop to print an Arraylist of different objects of different classes

Question

class Main
{
    public static void main(String[] args)
    {
        Scanner input = new Scanner(System.in);

        Loan loan = new Loan();
        Date date = new Date();
        Strings strings = new Strings();
        Frame frame = new Frame();
        Circle circle = new Circle();

        ArrayList<Object> mylist = new ArrayList<Object>();
        mylist.add(loan);
        mylist.add(date);
        mylist.add(strings);
        mylist.add(frame);
        mylist.add(circle);

        for (Object i : mylist)
        {
            System.out.println(mylist.get(i));
        }
         /*
         //this method is working fine
         System.out.println(mylist.get(0));
         System.out.println(mylist.get(1));
         System.out.println(mylist.get(2));
         System.out.println(mylist.get(3));
         System.out.println(mylist.get(4));

         //this method is also working fine
         for (int i = 0; i < 4; i++)
         {
            System.out.println(mylist.get(i));
         }*/

    }
}

My Arraylist is of diiferent object types and all have fields with values and a toString method in each class (so that the printing is possible).....If i dont use a loop and if i use an iterating loop its working fine but i want to use a for each loop i used the above syntax but its showing errors.

for (Object i : mylist) { System.out.println(i); }

davidxxx
– davidxxx

2018-05-21 10:12:52 +00:00
Commented May 21, 2018 at 10:12 — davidxxx
– davidxxx, Commented May 21, 2018 at 10:12

Honza Zidek · Accepted Answer · 2018-05-21 10:16:40Z

1

myList.forEach(System.out::println);

and do not declare myList as ArrayList, but as List only - prefer declaring variables as interfaces whenever available

answered May 21, 2018 at 10:16

Honza Zidek

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Comments

Shanu Gupta · Accepted Answer · 2018-05-21 10:13:38Z

0

Change

    for (Object i : mylist)
    {
        System.out.println(mylist.get(i));
    }

to

    for (Object i : mylist)
    {
        System.out.println(i);
    }

i in foreach loop is the object itself not the index.

answered May 21, 2018 at 10:13

Shanu Gupta

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davidxxx · Accepted Answer · 2018-05-21 10:21:08Z

0

Here :

for (Object i : mylist)
{
    System.out.println(mylist.get(i)); 
                                  ^----- error here
}

You invoke myList.get() with an Object variable as argument.
It is not valid at compile time as ArrayList.get() takes an int as parameter :

E java.util.ArrayList.get(int index)

In a some way you mix the foreach and the "basic for" syntax.
The "basic for" statement requires the use of the index :

for (int i=0; i<mylist.size(); i++) {
     System.out.println(myList.get(i)); 
}

But the foreach syntax simplifies that :

for (Object i : mylist) {
     System.out.println(i); 
}

answered May 21, 2018 at 10:21

davidxxx

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