Fatal exception

I get the following error when I try to run the codelab:
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.google.example.android.basicactivityrecognitiontransitionsample, PID: 10099
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.google.example.android.basicactivityrecognitiontransitionsample/com.google.example.android.basicactivityrecognitiontransitionsample.MainActivity}: java.lang.IllegalArgumentException: com.google.example.android.basicactivityrecognitiontransitionsample: Targeting S+ (version 31 and above) requires that one of FLAG_IMMUTABLE or FLAG_MUTABLE be specified when creating a PendingIntent.
Strongly consider using FLAG_IMMUTABLE, only use FLAG_MUTABLE if some functionality depends on the PendingIntent being mutable, e.g. if it needs to be used with inline replies or bubbles.
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3635)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3792)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:103)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2210)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loopOnce(Looper.java:201)
at android.os.Looper.loop(Looper.java:288)
at android.app.ActivityThread.main(ActivityThread.java:7839)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:548)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1003)
Caused by: java.lang.IllegalArgumentException: com.google.example.android.basicactivityrecognitiontransitionsample: Targeting S+ (version 31 and above) requires that one of FLAG_IMMUTABLE or FLAG_MUTABLE be specified when creating a PendingIntent.
Strongly consider using FLAG_IMMUTABLE, only use FLAG_MUTABLE if some functionality depends on the PendingIntent being mutable, e.g. if it needs to be used with inline replies or bubbles.
at android.app.PendingIntent.checkFlags(PendingIntent.java:375)
at android.app.PendingIntent.getBroadcastAsUser(PendingIntent.java:645)
at android.app.PendingIntent.getBroadcast(PendingIntent.java:632)
at com.google.example.android.basicactivityrecognitiontransitionsample.MainActivity.onCreate(MainActivity.java:136)
at android.app.Activity.performCreate(Activity.java:8051)
at android.app.Activity.performCreate(Activity.java:8031)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1329)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3608)
... 12 more

Start in MainActivity.java at onCreate line 136, where the PendingIntent is created, and compare the call with Android's Targeting S+ requirement shown in the stack trace. Verify the codelab launches successfully on Android 12 or newer without the fatal exception.

Written by the indexing model from the issue text.