Issue
The following INFO
level log appears repeatedly:
o.internal.platform.Platform#log: ALPN callback dropped: HTTP/2 is disabled. Is alpn-boot on the boot class path?
Resolution
This happens when the client talks to a server that supports http2, but the JVM does not have ALPN support. ALPN is supported in JDK 9 and later by default, and was backported to JDK 8u252. Upgrading to 8u252 or later will remove the log. See here for more details.
Workaround
If upgrading the JDK is not possible, set the the log level of com.squareup.okhttp.OkHttpClient
and okhttp3.OkHttpClient
to WARNING
.
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