TheAlgorithms/Java · error · IndexOutOfBoundsException

Position out of bounds

Error message

Position out of bounds

What it means

Thrown by CircleLinkedList.remove(int pos) when pos >= size or pos < 0. The list uses 0-based logical positions and the guard validates the index before walking the node chain. An invalid pos would dereference a null node pointer.

Source

Thrown at src/main/java/com/thealgorithms/datastructures/lists/CircleLinkedList.java:109

                sb.append(", ");
            }
            current = current.next;
        }
        sb.append(" ]");
        return sb.toString();
    }

    /**
     * Removes and returns the element at the specified position in the list.
     * Throws an IndexOutOfBoundsException if the position is invalid.
     *
     * @param pos the position of the element to remove
     * @return the value of the removed element
     * @throws IndexOutOfBoundsException if the position is out of range
     */
    public E remove(int pos) {
        if (pos >= size || pos < 0) {
            throw new IndexOutOfBoundsException("Position out of bounds");
        }

        Node<E> before = head;
        for (int i = 1; i <= pos; i++) {
            before = before.next;
        }
        Node<E> destroy = before.next;
        E saved = destroy.value;
        before.next = destroy.next;

        if (destroy == tail) {
            tail = before;
        }
        destroy = null;
        size--;
        return saved;
    }
}

View on GitHub (pinned to fdfb9a395b)

Solutions

1. Validate `pos >= 0 && pos < list.size()` before remove.
2. Guard for empty list separately.
3. Use `i < list.size()` (strict) in removal loops, and recompute size each iteration since remove shrinks it.
4. When removing multiple elements, decrement indices or iterate in reverse.

Example fix

// before
for (int i = 0; i <= list.size(); i++) list.remove(i);

// after
while (!list.isEmpty()) {
    list.remove(0);
}

if (pos >= 0 && pos < list.size()) {
    return list.remove(pos);
}

try {
    return list.remove(pos);
} catch (IndexOutOfBoundsException e) {
    // invalid pos — skip
}

When it happens

Trigger: Calling remove(size) (off-by-one treating size as a valid index). Calling remove on an empty list (size=0, any non-negative pos fails). Passing a negative index.

Common situations: Loop `for (int i = 0; i <= list.size(); i++) remove(i)` including the size boundary. Removing by an index from a parallel array sized differently. Negative index from an arithmetic underflow.

Related errors

• Position out of bounds
• Index: ${index}, Size: ${size}
• ${position}
• Cannot add null element to the list
• Cannot add null element to the list

AI-assisted analysis of TheAlgorithms/Java@fdfb9a395b (2026-08-13). Data as JSON: /api/errors/479ae4f4fda4d61f. Report an issue: GitHub.