bumptech/glide · error · IllegalArgumentException

Must not be empty.

Error message

Must not be empty.

What it means

Thrown by Preconditions.checkNotEmpty(Collection) when a non-null Collection is empty (collection.isEmpty()). Used internally where Glide requires at least one element: empty model lists, empty header maps, empty key sets, etc.

Source

Thrown at library/src/main/java/com/bumptech/glide/util/Preconditions.java:49

  public static <T> T checkNotNull(@Nullable T arg, @NonNull String message) {
    if (arg == null) {
      throw new NullPointerException(message);
    }
    return arg;
  }

  @NonNull
  public static String checkNotEmpty(@Nullable String string) {
    if (TextUtils.isEmpty(string)) {
      throw new IllegalArgumentException("Must not be null or empty");
    }
    return string;
  }

  @NonNull
  public static <T extends Collection<Y>, Y> T checkNotEmpty(@NonNull T collection) {
    if (collection.isEmpty()) {
      throw new IllegalArgumentException("Must not be empty.");
    }
    return collection;
  }
}

View on GitHub (pinned to eb14a895d8)

Solutions

1. Guard with if (!collection.isEmpty()) before calling the API
2. Provide a fallback branch (placeholder / skip load) for the empty case
3. Use Kotlin's collection.takeIf { it.isNotEmpty() }?.let { ... }
4. Validate parsed data upstream and either skip rendering or show an empty-state view

Example fix

// before
Glide.with(ctx).load(urls).into(imageView) // urls may be emptyList()

// after
if (urls.isNotEmpty()) {
  Glide.with(ctx).load(urls).into(imageView)
} else {
  imageView.setImageResource(R.drawable.placeholder)
}

if (urls.isNotEmpty()) {
  Glide.with(ctx).load(urls).into(imageView)
} else {
  imageView.setImageResource(R.drawable.placeholder)
}

fun <T> Collection<T>.isNonEmpty(): Boolean = !isEmpty()

When it happens

Trigger: Passing an empty List/Set/Map to a Glide API that requires at least one entry; e.g. an empty list of URLs to a multi-model load, an empty headers map, an empty set of decoder keys.

Common situations: UI state where a list of items is filtered down to zero before bind; deserialized JSON collections that came back empty; default-initialized empty collections passed where required.

Related errors

• Must not be null or empty
• sizeMultiplier must be between 0 and 1
• File unsuitable for memory mapping
• Multiplier must be >= 0
• sizeMultiplier must be between 0 and 1

AI-assisted analysis of bumptech/glide@eb14a895d8 (2026-08-14). Data as JSON: /api/errors/979b94d32d890f17. Report an issue: GitHub.