TheAlgorithms/Java · error · IllegalArgumentException

Insertion sort threshold must be between 1 and 1000

Error message

Insertion sort threshold must be between 1 and 1000

What it means

Thrown by the SpreadSort(int, int, int) constructor when insertionSortThreshold < 1 or > MAX_INSERTION_SORT_THRESHOLD (1000). The threshold controls when SpreadSort switches to insertion sort for small segments; values outside [1, 1000] defeat this optimization. The message interpolates the upper bound constant.

Source

Thrown at src/main/java/com/thealgorithms/sorts/SpreadSort.java:28

public class SpreadSort implements SortAlgorithm {
    private static final int MAX_INSERTION_SORT_THRESHOLD = 1000;
    private static final int MAX_INITIAL_BUCKET_CAPACITY = 1000;
    private static final int MAX_MIN_BUCKETS = 100;

    private final int insertionSortThreshold;
    private final int initialBucketCapacity;
    private final int minBuckets;

    /**
     * Constructor to initialize the SpreadSort algorithm with custom parameters.
     *
     * @param insertionSortThreshold the threshold for using insertion sort for small segments (1-1000)
     * @param initialBucketCapacity  the initial capacity for each bucket (1-1000)
     * @param minBuckets             the minimum number of buckets to use (1-100)
     */
    public SpreadSort(int insertionSortThreshold, int initialBucketCapacity, int minBuckets) {
        if (insertionSortThreshold < 1 || insertionSortThreshold > MAX_INSERTION_SORT_THRESHOLD) {
            throw new IllegalArgumentException("Insertion sort threshold must be between 1 and " + MAX_INSERTION_SORT_THRESHOLD);
        }
        if (initialBucketCapacity < 1 || initialBucketCapacity > MAX_INITIAL_BUCKET_CAPACITY) {
            throw new IllegalArgumentException("Initial bucket capacity must be between 1 and " + MAX_INITIAL_BUCKET_CAPACITY);
        }
        if (minBuckets < 1 || minBuckets > MAX_MIN_BUCKETS) {
            throw new IllegalArgumentException("Minimum number of buckets must be between 1 and " + MAX_MIN_BUCKETS);
        }

        this.insertionSortThreshold = insertionSortThreshold;
        this.initialBucketCapacity = initialBucketCapacity;
        this.minBuckets = minBuckets;
    }

    /**
     * Default constructor with predefined values.
     */
    public SpreadSort() {
        this(16, 16, 2);

View on GitHub (pinned to fdfb9a395b)

Solutions

1. Validate 1 <= insertionSortThreshold <= 1000 before constructing.
2. Clamp config-derived values into the valid range with a sensible default.
3. Document the [1, 1000] range in your config schema and validate at parse time.

Example fix

// before
SpreadSort s = new SpreadSort(threshold, cap, buckets);

// after
int t = Math.max(1, Math.min(1000, threshold));
SpreadSort s = new SpreadSort(t, cap, buckets);

if (insertionSortThreshold < 1 || insertionSortThreshold > 1000) throw new IllegalArgumentException("insertionSortThreshold must be in [1,1000]");

public static boolean isValidInsertionThreshold(int v) { return v >= 1 && v <= 1000; }

When it happens

Trigger: new SpreadSort(0, cap, buckets); new SpreadSort(1001, cap, buckets); new SpreadSort(-5, cap, buckets); loading the threshold from config without bounds checking.

Common situations: Config typo leaving the value at 0; formula computing a threshold that exceeds 1000 for large inputs; exposing the threshold to users without input validation.

Related errors

• Classification ratio must be between 0 and 1 (exclusive).
• Initial bucket capacity must be between 1 and 1000
• Minimum number of buckets must be between 1 and 100
• Alpha must be between 0 and 1.
• order must be greater than zero

AI-assisted analysis of TheAlgorithms/Java@fdfb9a395b (2026-08-13). Data as JSON: /api/errors/3c308992ac70541d. Report an issue: GitHub.