diff --git a/lib/shared/internal/src/main/java/com/launchdarkly/sdk/internal/events/PerContextEventSummarizer.java b/lib/shared/internal/src/main/java/com/launchdarkly/sdk/internal/events/PerContextEventSummarizer.java
index d621378c..35e34348 100644
--- a/lib/shared/internal/src/main/java/com/launchdarkly/sdk/internal/events/PerContextEventSummarizer.java
+++ b/lib/shared/internal/src/main/java/com/launchdarkly/sdk/internal/events/PerContextEventSummarizer.java
@@ -47,8 +47,12 @@ public void summarizeEvent(
     LDValue defaultValue,
     LDContext context
   ) {
-    // Get or create summarizer for this context
-    EventSummarizer summarizer = summarizersByContext.computeIfAbsent(context, EventSummarizer::new);
+    // Not computeIfAbsent: Android below API 24 has neither it nor java.util.function.
+    EventSummarizer summarizer = summarizersByContext.get(context);
+    if (summarizer == null) {
+      summarizer = new EventSummarizer(context);
+      summarizersByContext.put(context, summarizer);
+    }
 
     // Delegate to the per-context summarizer
     summarizer.summarizeEvent(timestamp, flagKey, flagVersion, variation, value, defaultValue, context);