UnsupportedOperationException on SSLSocket.shutdownOutput

[lon9man]

WHAT I DID

i use okhttp 5.2.0 in Jetpack Compose project. today tried latest Android Studio and emulator on Android API 23

Build #AI-251.26094.121.2513.14007798, built on August 28, 2025
Runtime version: 21.0.7+-13880790-b1038.58 aarch64
VM: OpenJDK 64-Bit Server VM by JetBrains s.r.o.
Toolkit: sun.lwawt.macosx.LWCToolkit
macOS 15.5
Kotlin plugin: K2 mode
GC: G1 Young Generation, G1 Concurrent GC, G1 Old Generation
Memory: 6144M
Cores: 14
Metal Rendering is ON
Registry:
  ide.instant.shutdown=false
  debugger.watches.in.variables=false
  completion.show.intention.icon=false
  ide.experimental.ui=true
Non-Bundled Plugins:
  com.intellij.plugins.xwinkeymap (211.4961.30)
  Docker (251.26094.141)
  com.intellij.plugins.gnomekeymap (213.4250.391)
  com.apollographql.ijplugin (5.0.0)
  com.developerphil.adbidea (1.6.19)

emulator properties:

Properties
avd.ini.displayname              Nexus 5 API 23
avd.ini.encoding                 UTF-8
AvdId                            Nexus_5_API_23
disk.dataPartition.size          2G
fastboot.chosenSnapshotFile      
fastboot.forceChosenSnapshotBoot no
fastboot.forceColdBoot           no
fastboot.forceFastBoot           yes
hw.accelerometer                 yes
hw.arc                           false
hw.audioInput                    yes
hw.battery                       yes
hw.camera.back                   virtualscene
hw.camera.front                  emulated
hw.cpu.ncore                     4
hw.device.hash2                  MD5:b2095f91cdc43a64f165f9b79403516f
hw.device.manufacturer           Google
hw.device.name                   Nexus 5
hw.dPad                          no
hw.gps                           yes
hw.gpu.enabled                   yes
hw.gpu.mode                      auto
hw.gyroscope                     yes
hw.initialOrientation            portrait
hw.keyboard                      yes
hw.lcd.density                   480
hw.lcd.height                    1920
hw.lcd.width                     1080
hw.mainKeys                      no
hw.ramSize                       2048
hw.sdCard                        yes
hw.sensors.light                 yes
hw.sensors.magnetic_field        yes
hw.sensors.orientation           yes
hw.sensors.pressure              yes
hw.sensors.proximity             yes
hw.trackBall                     no
image.sysdir.1                   system-images/android-23/google_apis/arm64-v8a/
PlayStore.enabled                false
runtime.network.latency          none
runtime.network.speed            full
showDeviceFrame                  yes
skin.dynamic                     yes
tag.display                      Google APIs
tag.displaynames                 Google APIs
tag.id                           google_apis
tag.ids                          google_apis
target                           android-23
vm.heapSize                      128

WHAT I GOT

Process: xxx, PID: 3403
java.lang.UnsupportedOperationException
  at javax.net.ssl.SSLSocket.shutdownOutput(SSLSocket.java:851)
  at okio.internal.DefaultSocket$SocketSink.close(DefaultSocket.kt:95)
  at okio.RealBufferedSink.close(RealBufferedSink.kt:287)
  at okhttp3.internal.http2.Http2Writer.close(Http2Writer.kt:331)
  at okhttp3.internal.http2.Http2Connection.close$okhttp(Http2Connection.kt:474)
  at okhttp3.internal.http2.Http2Connection$ReaderRunnable.invoke(Http2Connection.kt:638)
  at okhttp3.internal.http2.Http2Connection$ReaderRunnable.invoke(Http2Connection.kt:619)
  at okhttp3.internal.concurrent.TaskQueue$execute$1.runOnce(TaskQueue.kt:112)
  at okhttp3.internal.concurrent.TaskRunner$runnable$1.run(TaskRunner.kt:81)
  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1113)
  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:588)
  at java.lang.Thread.run(Thread.java:818)

[yschimke]

Which version have you upgrade from? And is it happening in the app, or in tests with mock server?

We started using a new Okio Socket code path in 5.0 alphas. https://github.com/square/okhttp/blob/master/CHANGELOG.md#version-500-alpha17

I think in 5.2.0 we didn't change much here, apart from mock web server https://github.com/square/okhttp/compare/parent-5.1.0..parent-5.2.0#diff-a2ddaa4d134c145c5aa342a36124e405b5d4bff1eb7170f6abf8a3317599b6b8

[lon9man]

@yschimke before i used 4.12.0. it is app (not mock server).
yesterday tried run on real device Nexus 5 (6.0.1). result is the same:

2025-10-08 21:15:18.664 32202-32386 AndroidRuntime          pid-32202                            E  FATAL EXCEPTION: OkHttp TaskRunner
Process: xxx, PID: 32202
java.lang.UnsupportedOperationException
  at javax.net.ssl.SSLSocket.shutdownOutput(SSLSocket.java:851)
  at okio.internal.DefaultSocket$SocketSink.close(DefaultSocket.kt:95)
  at okio.RealBufferedSink.close(RealBufferedSink.kt:287)
  at okhttp3.internal.http2.Http2Writer.close(Http2Writer.kt:331)
  at okhttp3.internal.http2.Http2Connection.close$okhttp(Http2Connection.kt:474)
  at okhttp3.internal.http2.Http2Connection$ReaderRunnable.invoke(Http2Connection.kt:638)
  at okhttp3.internal.http2.Http2Connection$ReaderRunnable.invoke(Http2Connection.kt:619)
  at okhttp3.internal.concurrent.TaskQueue$execute$1.runOnce(TaskQueue.kt:112)
  at okhttp3.internal.concurrent.TaskRunner$runnable$1.run(TaskRunner.kt:81)
  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1113)
  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:588)
  at java.lang.Thread.run(Thread.java:818)

now reverted to 4.12.0 - it seems app works as expected

[yschimke]

OK, I'll try later with a local emulator.

We run CI against 21, 29, 34

So strange it's failing this way https://github.com/square/okhttp/blob/master/.github/workflows/build.yml#L495

If I can't reproduce locally, then a simple empty project in github that reproduces would help. But I'll try reproducing myself first tonight.

[yschimke]

Yep, can reproduce on API 23 emulator

21:17:37.696  E  FATAL EXCEPTION: OkHttp TaskRunner (Ask Gemini)
                 Process: okhttp.android.testapp, PID: 4978
                 java.lang.UnsupportedOperationException
                 	at javax.net.ssl.SSLSocket.shutdownOutput(SSLSocket.java:851)
                 	at okio.internal.DefaultSocket$SocketSink.close(DefaultSocket.kt:95)
                 	at okio.RealBufferedSink.close(RealBufferedSink.kt:287)
                 	at okhttp3.internal.http2.Http2Writer.close(Http2Writer.kt:331)
                 	at okhttp3.internal.http2.Http2Connection.close$okhttp(Http2Connection.kt:474)
                 	at okhttp3.internal.http2.Http2Connection$ReaderRunnable.invoke(Http2Connection.kt:638)
                 	at okhttp3.internal.http2.Http2Connection$ReaderRunnable.invoke(Http2Connection.kt:619)
                 	at okhttp3.internal.concurrent.TaskQueue$execute$1.runOnce(TaskQueue.kt:112)
                 	at okhttp3.internal.concurrent.TaskRunner$runnable$1.run(TaskRunner.kt:81)
                 	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1113)
                 	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:588)
                 	at java.lang.Thread.run(Thread.java:818)

[yschimke]

https://android.googlesource.com/platform/libcore2/+/master/luni/src/main/java/javax/net/ssl/SSLSocket.java#133 Confirming this impl

[yschimke]

Combination of two issues

1. This appears to be part of the SSLSocket impl in API 21 and 23

2. tests are skipping on API 21-25. That's why we missed this.

21:45:24.987  I  ignored: testUnderscoreRequest(okhttp.android.test.OkHttpTest)
21:45:24.988  W  JUnit 5 is not supported on this device: API level 23 is less than 26, the minimum requirement. All Jupiter tests for okhttp.android.test.alpn.AlpnOverrideTest will be disabled.

[yschimke]

Confirmed working fine on API 24.

[lon9man]

@yschimke
Thanks for the fast response and useful investigation!
What is the expected timing for release?

[yschimke]

Soonish...

From @swankjesse:

Jesse Wilson
10:56 PM
⚠️ Heads up: OkHttp 5.2.0 is crashing on API levels 21 through 23. We’re cutting OkHttp 5.2.1 to fix. Details here.