How to Remove Objects from an Array in Java

How can I remove all occurrences of a specific object from an array in Java?

String[] foo = new String[] {"a", "cc", "a", "dd"};

Removing objects from an array in Java involves creating a new array since Java arrays have a fixed size. Here’s how to remove all occurrences of a specific string, such as 'a', from a string array.

import java.util.ArrayList;
import java.util.Arrays;

public class RemoveElements {
    public static void main(String[] args) {
        String[] foo = {"a", "cc", "a", "dd"};
        // Convert array to ArrayList
        ArrayList<String> list = new ArrayList<>(Arrays.asList(foo));
        // Remove all occurrences of "a"
        list.removeIf(s -> s.equals("a"));
        // Convert back to array
        String[] result = list.toArray(new String[0]);
        System.out.println(Arrays.toString(result)); // Output: [cc, dd]
    }
}

Causes

• Fixed-size nature of arrays in Java complicates direct removal.
• Removing elements requires creating a new array or using a list.

Solutions

• Create a new array to hold the filtered values.
• Use an ArrayList for dynamic resizing, which simplifies element removal.

Mistake: Not reassigning the modified array to a new variable after filtering.

Solution: Always store the result of the filtering process into a new array or collection.

Mistake: Using a loop to remove elements from an array without creating a new array.

Solution: Instead of modifying the array during iteration, create a new collection to hold the desired elements.