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Java LinkedList retainAll() Method

Flash cards

Review the key moves

1/4
Core idea

What is the main idea behind Java LinkedList retainAll() Method?

Lesson checks

Practice each idea before moving on

Short Mimo-style checks built from this lesson's code, terms, and sequence.

1Quick choice

Which statement best captures the main point of this lesson?

2Fill blank

Complete the missing token from the example code.

___ java.util.LinkedList;
3Order

Put the learning moves in the order that makes the concept easiest to apply.

The retainAll() method removes all items from a list which do not belong to a specified collection.
Definition and Usage
Java LinkedList retainAll() Method

❮ LinkedList Methods

Example

import java.util.LinkedList;
public class Main {
  public static void main(String[] args) {
    LinkedList<String> cars = new LinkedList<String>();
    cars.add("Volvo");
    cars.add("BMW");
    cars.add("Ford");
    cars.add("Mazda");
    cars.add("Toyota");
    LinkedList<String> valid = new LinkedList<String>();
    valid.add("Volvo");
    valid.add("Ford");
    valid.add("Mazda");
    cars.retainAll(valid);
    System.out.println(cars);
  }
}

Definition and Usage

The retainAll() method removes all items from a list which do not belong to a specified collection.

Syntax

public boolean retainAll(Collection
items )

Parameter Values

ParameterDescription
itemsRequired. A collection containing the items to keep in the list while all others are removed.

Technical Details

Returns:true if the list changed and false otherwise.
Throws:NullPointerException - If the collection is null.

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Java LinkedList set() Method