diff --git a/common/src/main/java/dev/cel/common/internal/AdaptingTypes.java b/common/src/main/java/dev/cel/common/internal/AdaptingTypes.java
index 48158bd91..4cfe1ff4a 100644
--- a/common/src/main/java/dev/cel/common/internal/AdaptingTypes.java
+++ b/common/src/main/java/dev/cel/common/internal/AdaptingTypes.java
@@ -118,7 +118,12 @@ public Iterator<B> iterator() {
 
     @Override
     public Object[] toArray() {
-      return delegate.stream().map(baseEl -> converter().convert(baseEl)).toArray();
+      Object[] result = new Object[size()];
+      int i = 0;
+      for (A a : delegate) {
+        result[i++] = converter().convert(a);
+      }
+      return result;
     }
 
     @Override
diff --git a/runtime/src/main/java/dev/cel/runtime/Activation.java b/runtime/src/main/java/dev/cel/runtime/Activation.java
index 074a461a2..11328fb1c 100644
--- a/runtime/src/main/java/dev/cel/runtime/Activation.java
+++ b/runtime/src/main/java/dev/cel/runtime/Activation.java
@@ -109,11 +109,9 @@ public static Activation copyOf(Map<String, ?> map) {
     final ImmutableMap<String, Object> copy =
         (map instanceof ImmutableMap)
             ? (ImmutableMap<String, Object>) map
-            : map.entrySet().stream()
-                // ImmutableMaps are null-hostile, but the Activation is not, so make sure that null
-                // values and entries are skipped.
-                .filter(entry -> entry.getKey() != null && entry.getValue() != null)
-                .collect(toImmutableMap(Map.Entry::getKey, Map.Entry::getValue));
+            : // ImmutableMaps are null-hostile, but the Activation is not, so make sure that null
+            // values and entries are skipped.
+            toImmutableMapFilteringNulls(map);
     return new Activation() {
 
       @Override
@@ -128,6 +126,23 @@ public String toString() {
     };
   }
 
+  /**
+   * Creates an {@link ImmutableMap} from the given {@link Map} filtering out null keys and values.
+   *
+   * <p>Used instead of the one-liner for performance reasons.
+   */
+  private static ImmutableMap<String, Object> toImmutableMapFilteringNulls(Map<String, ?> map) {
+    ImmutableMap.Builder<String, Object> builder = ImmutableMap.builderWithExpectedSize(map.size());
+    for (Map.Entry<String, ?> entry : map.entrySet()) {
+      String key = entry.getKey();
+      Object value = entry.getValue();
+      if (key != null && value != null) {
+        builder.put(key, value);
+      }
+    }
+    return builder.buildOrThrow();
+  }
+
   /**
    * Extends this binder by another binder. Names will be attempted to first resolve in the other
    * binder, then in this binder.
diff --git a/runtime/src/main/java/dev/cel/runtime/DefaultInterpreter.java b/runtime/src/main/java/dev/cel/runtime/DefaultInterpreter.java
index fa22b1d00..ab268850d 100644
--- a/runtime/src/main/java/dev/cel/runtime/DefaultInterpreter.java
+++ b/runtime/src/main/java/dev/cel/runtime/DefaultInterpreter.java
@@ -499,7 +499,10 @@ private IntermediateResult dispatchCall(
         return IntermediateResult.create(attr, unknowns.get());
       }
 
-      Object[] argArray = Arrays.stream(argResults).map(IntermediateResult::value).toArray();
+      Object[] argArray = new Object[argResults.length];
+      for (int i = 0; i < argResults.length; i++) {
+        argArray[i] = argResults[i].value();
+      }
       ImmutableList<String> overloadIds = reference.overloadIds();
       CelResolvedOverload overload =
           findOverloadOrThrow(frame, expr, callExpr.function(), overloadIds, argArray);