Looping Through an ArrayList in java

The size() method to define that how many times the loop should run. The looping through the principle of an ArrayList with a for loop

public class Main { 
  public static void main(String[] args) { 
    ArrayList<String> mobiles = new ArrayList<String>();
    mobiles.add("Samsung");
    mobiles.add("Apple");
    mobiles.add("Nokia");
    mobiles.add("Sony");
    for (int i = 0; i < mobiles.size(); i++) {
      System.out.println(mobiles.get(i));
    }
  } 
}

You can also loop over an ArrayList with the for-each loop:

import java.util.ArrayList;

public class Main { 
  public static void main(String[] args) { 
    ArrayList<String> mobiles = new ArrayList<String>();
    mobiles.add("Samsung");
    mobiles.add("Apple");
    mobiles.add("Nokia");
    mobiles.add("Sony");
    for (String i : mobiles) {
      System.out.println(i);
    }
  } 
}

String in Java is an object. You must specify an equivalent wrapper class, To use other types, such as int,
Integer. For other primitive types,
For other primitive types, use: 
Boolean for boolean, 
Character for char, 
Double for double, etc

Example
Create an ArrayList to store numbers (To Add elements of type Integer):

import java.util.ArrayList;

public class Main { 
  public static void main(String[] args) { 
    ArrayList<Integer> newNumbers = new ArrayList<Integer>();
    newNumbers.add(100);
    newNumbers.add(315);
    newNumbers.add(120);
    newNumbers.add(245);
    for (int x : newNumbers) {
      System.out.println(x);
    }
  } 
}