didi/DoKit · error · NullPointerException

key == null || bitmap == null

Error message

key == null || bitmap == null

What it means

LruCache.set() throws NullPointerException when either the key or the bitmap is null. Storing a null bitmap would corrupt accounting (byte sizes) and a null key could never be retrieved, so both are rejected. Fail-fast guard.

Source

Thrown at Android/dokit/src/main/java/com/didichuxing/doraemonkit/picasso/LruCache.java:69

      throw new NullPointerException("key == null");
    }

    Bitmap mapValue;
    synchronized (this) {
      mapValue = map.get(key);
      if (mapValue != null) {
        hitCount++;
        return mapValue;
      }
      missCount++;
    }

    return null;
  }

  @Override public void set(String key, Bitmap bitmap) {
    if (key == null || bitmap == null) {
      throw new NullPointerException("key == null || bitmap == null");
    }

    Bitmap previous;
    synchronized (this) {
      putCount++;
      size += Utils.getBitmapBytes(bitmap);
      previous = map.put(key, bitmap);
      if (previous != null) {
        size -= Utils.getBitmapBytes(previous);
      }
    }

    trimToSize(maxSize);
  }

  private void trimToSize(int maxSize) {
    while (true) {
      String key;

View on GitHub (pinned to 626827cddb)

Solutions

1. Only call set() when both key and bitmap are non-null
2. Check the decode result: skip caching when the factory returned null
3. Guarantee key generation (stableKey/URI/resourceId) before any cache interaction

Example fix

// before
Bitmap b = decode(data);
cache.set(key, b); // NullPointerException when b == null

// after
Bitmap b = decode(data);
if (b != null && key != null) {
  cache.set(key, b);
}

if (key != null && bitmap != null) { cache.set(key, bitmap); }

boolean canCache(String key, Bitmap bitmap) { return key != null && bitmap != null; }

When it happens

Trigger: Calling cache.set(key, null) after a decode returned null, or cache.set(null, bitmap) when the cache key is missing.

Common situations: Caching a decode result without checking decode success; cache key derived from a URI that is null for resource-ID requests.

Related errors

• Memory cache must not be null.
• key == null
• uri == null
• path == null
• file == null

AI-assisted analysis of didi/DoKit@626827cddb (2026-08-14). Data as JSON: /api/errors/cf34207f89081163. Report an issue: GitHub.