This example demonstrates how to access remove an element from ArrayList in Java.

How to Remove Element from ArrayList in Java

This example shows different ways to remove an element from ArrayList in Java.

• How to remove the element at a given index in an ArrayList | remove(int index)
• How to remove an element from an ArrayList  | remove(Object o)
• How to remove all the elements from an ArrayList  that exist in a given collection | removeAll()
• How to remove all the elements matching a given Predicate | removeIf()
• How to clear an ArrayList  | clear()

import java.util.ArrayList;
import java.util.List;
import java.util.function.Predicate;

public class RemoveElementsFromArrayListExample {
    public static void main(String[] args) {
        List<String> programmingLanguages = new ArrayList<>();
        programmingLanguages.add("C");
        programmingLanguages.add("C++");
        programmingLanguages.add("Java");
        programmingLanguages.add("Kotlin");
        programmingLanguages.add("Python");
        programmingLanguages.add("Perl");
        programmingLanguages.add("Ruby");

        System.out.println("Initial List: " + programmingLanguages);

        // Remove the element at index `5`
        programmingLanguages.remove(5);
        System.out.println("After remove(5): " + programmingLanguages);

        // Remove the first occurrence of the given element from the ArrayList
        // (The remove() method returns false if the element does not exist in the ArrayList)
        boolean isRemoved = programmingLanguages.remove("Kotlin");
        System.out.println("After remove(\"Kotlin\"): " + programmingLanguages);

        // Remove all the elements that exist in a given collection
        List<String> scriptingLanguages = new ArrayList<>();
        scriptingLanguages.add("Python");
        scriptingLanguages.add("Ruby");
        scriptingLanguages.add("Perl");

        programmingLanguages.removeAll(scriptingLanguages);
        System.out.println("After removeAll(scriptingLanguages): " + programmingLanguages);

        // Remove all the elements that satisfy the given predicate
        programmingLanguages.removeIf(new Predicate<String>() {
            @Override
            public boolean test(String s) {
                return s.startsWith("C");
            }
        });

        /*
            The above removeIf() call can also be written using lambda expression like this -
            programmingLanguages.removeIf(s -> s.startsWith("C"))
        */

        System.out.println("After Removing all elements that start with \"C\": " + programmingLanguages);

        // Remove all elements from the ArrayList
        programmingLanguages.clear();
        System.out.println("After clear(): " + programmingLanguages);
    }
}

Output

Initial List: [C, C++, Java, Kotlin, Python, Perl, Ruby]
After remove(5): [C, C++, Java, Kotlin, Python, Ruby]
After remove("Kotlin"): [C, C++, Java, Python, Ruby]
After removeAll(scriptingLanguages): [C, C++, Java]
After Removing all elements that start with "C": [Java]
After clear(): []

Reference

https://www.javaguides.net/2018/11/java-arraylist-class-methods-with-examples.html