Fix PointAnnotationClusterActivity NPE crash on invalid HTTP response (#10413)

## Summary

Fixes: https://mapbox.atlassian.net/browse/MAPSAND-2547

- Fix NPE crash in `PointAnnotationClusterActivity` when the network
request for GeoJSON data returns an error response
- Add HTTP error checking in `AnnotationUtils.loadStringFromNet()` to
return `null` on non-2xx responses instead of passing a null/empty body
downstream
- Add GeoJSON parse error handling with user-facing `Toast` messages in
both the `app` and `compose-app` examples

## Problem

Reported via mobot tests on Samsung Galaxy S22, Android 13,
v11.19.0-beta.1. The examples app crashes with `NullPointerException:
Null type` when tapping "Add Cluster Symbol Annotations".

#### Root cause analysis from logcat

1. The ArcGIS URL (`opendata.arcgis.com`) returns a **301 redirect** to
`hub.arcgis.com`, which intermittently serves non-GeoJSON content (HTML
error pages instead of the expected `.geojson` response).
2. `loadStringFromNet()` **never checks `response.isSuccessful`** — it
reads the response body unconditionally, even on 4xx/5xx error codes.
The HTML error page is returned as a valid `String`.
3. The HTML string is passed directly to `FeatureCollection.fromJson()`,
which throws an NPE because there is no `"type"` field in the response
(AutoValue's generated code performs a null check on the required `type`
property).
4. Two identical crashes occurred **39 seconds apart** with different
PIDs, confirming the endpoint was consistently returning bad content
during that time window.
5. The 551 "Unable to make space for entry" cache warning messages
visible in the same logcat are **unrelated** — they originate from
maps-core's tile cache on a different thread, triggered by an earlier
offline download, and are not connected to this crash.

## Solution

Check `response.isSuccessful` in `AnnotationUtils` before reading the
body, returning `null` early on HTTP errors. In both
`PointAnnotationClusterActivity` variants, null-check the result before
parsing, wrap JSON parsing in a `try/catch`, and show a `Toast` on
failure. The Compose variant also removes the now-unnecessary
`suspendCancellableCoroutine`/`ExperimentalCoroutinesApi` wrapper.

## Key Changes

- **`AnnotationUtils.loadStringFromNet()`** (`app` + `compose-app`):
Check `response.isSuccessful`; log and return `null` on HTTP errors.
Replace manual `BufferedReader`/`StringBuilder` with
`response.body?.string()`.
- **`app/.../markersandcallouts/PointAnnotationClusterActivity`**:
Null-check `loadStringFromNet()` result, wrap
`FeatureCollection.fromJson()` in `try/catch`, show `Toast` on failure,
add `TAG` constant.
- **`compose-app/.../annotation/PointAnnotationClusterActivity`**: Same
null/parse error handling; refactored `loadData()` from
`suspendCancellableCoroutine` to a plain `fun` returning `emptyList()`
on failure; removed `@OptIn(ExperimentalCoroutinesApi::class)`.
- **Imports**: Replaced wildcard `java.io.*` with explicit imports in
both `AnnotationUtils` files.

## Test plan

- [x] Manually test `PointAnnotationClusterActivity` in `app` with
network available
- [x] Manually test `PointAnnotationClusterActivity` in `compose-app`
with network available
- [x] Manually test with network disabled to confirm `Toast` error
message appears

cc @mapbox/sdk-platform
cc @mapbox/maps-android

GitOrigin-RevId: fc93f22b63f964e2375915d626614b00b28efb2e

Author: pengdev

CHANGELOG.md

@@ -9,6 +9,9 @@ Mapbox welcomes participation and contributions from everyone.
 ## Features ✨ and improvements 🏁
 * [compose] Add declarative animation API to experimental `Marker` composable with two animation triggers: `appearAnimation` and `disappearAnimation`. Each trigger accepts a list of `MarkerAnimationEffect` including `wiggle` (pendulum rotation), `scale`, `fadeIn`, and `fadeOut`. Effects can be customized with parameters (e.g., `scale(from = 0.5f, to = 1.5f)`, `fade(from = 0.5f, to = 1.0f)`) and combined for rich animations. See `MarkersActivity` example for usage.
 
+## Bug fixes 🐞
+* Fix NPE crash in `PointAnnotationClusterActivity` example when the remote GeoJSON endpoint returns a non-successful HTTP response.
+
 # 11.19.0-rc.1 February 12, 2026
 
 ## Features ✨ and improvements 🏁

app/src/main/java/com/mapbox/maps/testapp/examples/annotation/AnnotationUtils.kt

@@ -10,8 +10,8 @@ import kotlinx.coroutines.withContext
 import okhttp3.Cache
 import okhttp3.OkHttpClient
 import okhttp3.Request
-import java.io.*
-import java.nio.charset.Charset
+import java.io.File
+import java.io.IOException
 import java.util.*
 
 /**
@@ -117,13 +117,12 @@ object AnnotationUtils {
 
     return try {
       val response = client.newCall(request).execute()
-      val inputStream = BufferedInputStream(response.body?.byteStream())
-      val rd = BufferedReader(InputStreamReader(inputStream, Charset.forName("UTF-8")))
-      val sb = StringBuilder()
-      rd.forEachLine {
-        sb.append(it)
+      if (!response.isSuccessful) {
+        logE(TAG, "HTTP error ${response.code} for $url")
+        response.close()
+        return null
       }
-      sb.toString()
+      response.body?.string()
     } catch (e: IOException) {
       logE(TAG, "Unable to download $url")
       null

app/src/main/java/com/mapbox/maps/testapp/examples/markersandcallouts/PointAnnotationClusterActivity.kt

@@ -12,6 +12,7 @@ import com.mapbox.maps.MapboxMap
 import com.mapbox.maps.Style
 import com.mapbox.maps.extension.style.expressions.dsl.generated.literal
 import com.mapbox.maps.extension.style.expressions.generated.Expression.Companion.color
+import com.mapbox.maps.logE
 import com.mapbox.maps.plugin.annotation.AnnotationConfig
 import com.mapbox.maps.plugin.annotation.AnnotationSourceOptions
 import com.mapbox.maps.plugin.annotation.ClusterOptions
@@ -141,14 +142,27 @@ class PointAnnotationClusterActivity : AppCompatActivity(), CoroutineScope {
   }
 
   private fun loadData() {
-    AnnotationUtils.loadStringFromNet(this@PointAnnotationClusterActivity, POINTS_URL)?.let {
-      FeatureCollection.fromJson(it).features()?.let { features ->
+    val json = AnnotationUtils.loadStringFromNet(this@PointAnnotationClusterActivity, POINTS_URL)
+    if (json == null) {
+      runOnUiThread {
+        Toast.makeText(this@PointAnnotationClusterActivity, "Failed to download data from network", Toast.LENGTH_LONG).show()
+        binding.progress.visibility = View.GONE
+      }
+      return
+    }
+    try {
+      FeatureCollection.fromJson(json).features()?.let { features ->
         features.shuffle()
         options = features.take(AMOUNT).map { feature ->
           PointAnnotationOptions()
             .withGeometry((feature.geometry() as Point))
         }
       }
+    } catch (e: Exception) {
+      logE(TAG, "Failed to parse GeoJSON: ${e.message}")
+      runOnUiThread {
+        Toast.makeText(this@PointAnnotationClusterActivity, "Failed to parse GeoJSON: ${e.message}", Toast.LENGTH_LONG).show()
+      }
     }
     runOnUiThread {
       options?.let {
@@ -159,6 +173,7 @@ class PointAnnotationClusterActivity : AppCompatActivity(), CoroutineScope {
   }
 
   companion object {
+    private const val TAG = "PointAnnotationCluster"
     private const val AMOUNT = 10000
     private const val ICON_FIRE_STATION = "fire-station"
     private const val LONGITUDE = -77.00897

compose-app/src/main/java/com/mapbox/maps/compose/testapp/examples/annotation/PointAnnotationClusterActivity.kt

@@ -30,13 +30,12 @@ import com.mapbox.maps.extension.compose.style.standard.ThemeValue
 import com.mapbox.maps.extension.compose.style.standard.rememberStandardStyleState
 import com.mapbox.maps.extension.style.expressions.dsl.generated.literal
 import com.mapbox.maps.extension.style.expressions.generated.Expression
+import com.mapbox.maps.logE
 import com.mapbox.maps.plugin.annotation.AnnotationConfig
 import com.mapbox.maps.plugin.annotation.AnnotationSourceOptions
 import com.mapbox.maps.plugin.annotation.ClusterOptions
 import com.mapbox.maps.plugin.annotation.generated.PointAnnotationOptions
 import kotlinx.coroutines.Dispatchers
-import kotlinx.coroutines.ExperimentalCoroutinesApi
-import kotlinx.coroutines.suspendCancellableCoroutine
 import kotlinx.coroutines.withContext
 
 /**
@@ -152,25 +151,31 @@ public class PointAnnotationClusterActivity : ComponentActivity() {
     }
   }
 
-  @OptIn(ExperimentalCoroutinesApi::class)
-  private suspend fun loadData(): List<Point> {
-    return suspendCancellableCoroutine { continuation ->
-      AnnotationUtils.loadStringFromNet(this@PointAnnotationClusterActivity, POINTS_URL)
-        ?.let {
-          FeatureCollection.fromJson(it).features()?.let { features ->
-            features.shuffle()
-            continuation.resume(
-              features.take(AMOUNT).map { feature ->
-                feature.geometry() as Point
-              },
-              onCancellation = null
-            )
-          }
+  private fun loadData(): List<Point> {
+    val json = AnnotationUtils.loadStringFromNet(this@PointAnnotationClusterActivity, POINTS_URL)
+    if (json == null) {
+      runOnUiThread {
+        Toast.makeText(this@PointAnnotationClusterActivity, "Failed to download data from network", Toast.LENGTH_LONG).show()
+      }
+      return emptyList()
+    }
+    return try {
+      FeatureCollection.fromJson(json).features()?.let { features ->
+        features.shuffled().take(AMOUNT).map { feature ->
+          feature.geometry() as Point
         }
+      } ?: emptyList()
+    } catch (e: Exception) {
+      logE(TAG, "Failed to parse GeoJSON: ${e.message}")
+      runOnUiThread {
+        Toast.makeText(this@PointAnnotationClusterActivity, "Failed to parse GeoJSON: ${e.message}", Toast.LENGTH_LONG).show()
+      }
+      emptyList()
     }
   }
 
   private companion object {
+    const val TAG = "PointAnnotationCluster"
     const val ZOOM: Double = 10.0
     const val AMOUNT = 10000
     const val ICON_FIRE_STATION = "fire-station"

compose-app/src/main/java/com/mapbox/maps/compose/testapp/examples/utils/AnnotationUtils.kt

@@ -7,7 +7,10 @@ import com.mapbox.maps.logE
 import okhttp3.Cache
 import okhttp3.OkHttpClient
 import okhttp3.Request
-import java.io.*
+import java.io.BufferedReader
+import java.io.File
+import java.io.IOException
+import java.io.InputStreamReader
 import java.nio.charset.Charset
 import java.util.*
 
@@ -112,13 +115,12 @@ internal object AnnotationUtils {
 
     return try {
       val response = client.newCall(request).execute()
-      val inputStream = BufferedInputStream(response.body?.byteStream())
-      val rd = BufferedReader(InputStreamReader(inputStream, Charset.forName("UTF-8")))
-      val sb = StringBuilder()
-      rd.forEachLine {
-        sb.append(it)
+      if (!response.isSuccessful) {
+        logE(TAG, "HTTP error ${response.code} for $url")
+        response.close()
+        return null
       }
-      sb.toString()
+      response.body?.string()
     } catch (e: IOException) {
       logE(TAG, "Unable to download $url")
       null