diff --git a/library/core/src/main/java/com/google/android/exoplayer2/drm/DefaultDrmSession.java b/library/core/src/main/java/com/google/android/exoplayer2/drm/DefaultDrmSession.java
index 0d93ec7c62..432cc6613f 100644
--- a/library/core/src/main/java/com/google/android/exoplayer2/drm/DefaultDrmSession.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/drm/DefaultDrmSession.java
@@ -41,7 +41,6 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.UUID;
-import org.checkerframework.checker.nullness.compatqual.NullableType;
 import org.checkerframework.checker.nullness.qual.EnsuresNonNullIf;
 import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
 import org.checkerframework.checker.nullness.qual.RequiresNonNull;
@@ -122,8 +121,8 @@ import org.checkerframework.checker.nullness.qual.RequiresNonNull;
   @Nullable private RequestHandler requestHandler;
   @Nullable private T mediaCrypto;
   @Nullable private DrmSessionException lastException;
-  private byte @NullableType [] sessionId;
-  private byte @MonotonicNonNull [] offlineLicenseKeySetId;
+  @Nullable private byte[] sessionId;
+  @MonotonicNonNull private byte[] offlineLicenseKeySetId;
 
   @Nullable private KeyRequest currentKeyRequest;
   @Nullable private ProvisionRequest currentProvisionRequest;
@@ -148,6 +147,8 @@ import org.checkerframework.checker.nullness.qual.RequiresNonNull;
    * @param loadErrorHandlingPolicy The {@link LoadErrorHandlingPolicy} for key and provisioning
    *     requests.
    */
+  // the constructor does not initialize fields: sessionId
+  @SuppressWarnings("nullness:initialization.fields.uninitialized")
   public DefaultDrmSession(
       UUID uuid,
       ExoMediaDrm<T> mediaDrm,
diff --git a/library/core/src/main/java/com/google/android/exoplayer2/extractor/MpegAudioHeader.java b/library/core/src/main/java/com/google/android/exoplayer2/extractor/MpegAudioHeader.java
index 8412b738bb..04d85b8bc5 100644
--- a/library/core/src/main/java/com/google/android/exoplayer2/extractor/MpegAudioHeader.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/extractor/MpegAudioHeader.java
@@ -15,9 +15,9 @@
  */
 package com.google.android.exoplayer2.extractor;
 
+import androidx.annotation.Nullable;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.util.MimeTypes;
-import org.checkerframework.checker.nullness.qual.Nullable;
 
 /**
  * An MPEG audio frame header.