The syntax of the forEach()
method is:
arraylist.forEach(Consumer<E> action)
Here, arraylist is an object of the ArrayList
class.
forEach() Parameters
The forEach()
method takes a single parameter.
- action - actions to be performed on each element of the arraylist
forEach() Return Value
The forEach()
method does not return any value.
Example: Java ArrayList forEach()
import java.util.ArrayList;
class Main {
public static void main(String[] args) {
// create an ArrayList
ArrayList<Integer> numbers = new ArrayList<>();
// add elements to the ArrayList
numbers.add(1);
numbers.add(2);
numbers.add(3);
numbers.add(4);
System.out.println("ArrayList: " + numbers);
// multiply 10 to all elements
System.out.print("Updated ArrayList: ");
// pass lambda expression to forEach()
numbers.forEach((e) -> {
e = e * 10;
System.out.print(e + " ");
});
}
}
Output
ArrayList: [1, 2, 3, 4] Updated ArrayList: 10 20 30 40
In the above example, we have created an arraylist named numbers. Notice the code,
numbers.forEach((e) -> {
e = e * 10;
System.out.print(e + " ");
});
Here, we have passed the lambda expression as an argument to the forEach()
method. The lambda expression multiplies each element of the arraylist by 10 and print the resultant value.
To learn more about lambda expression, visit Java Lambda Expressions.
Note: The forEach()
method is not the same as the for-each loop. We can use the Java for-each loop to iterate through each element of the arraylist.