Carrier threads pinned on object.wait() for Generativeaiinterferenceclient

[NarendraBanothu]

observed thread pinning happening for GenerativeAiInferenceClient for Helidon 4x version for AI calls for OCI sdk.

#2270 "[0x453f951d 0x5e59747f] WebServer socket" virtual
java.base/java.lang.Object.wait0(Native Method)
java.base/java.lang.Object.wait(Object.java:366)
java.base/java.lang.Object.wait(Object.java:339)
com.oracle.bmc.http.internal.SyncFutureWaiter$Waiter.waitAndWork(SyncFutureWaiter.java:61)
com.oracle.bmc.http.internal.SyncFutureWaiter.listenForResult(SyncFutureWaiter.java:32)
com.oracle.bmc.http.internal.ClientCall.callSync(ClientCall.java:1101)
com.oracle.bmc.generativeaiinference.GenerativeAiInferenceClient.chat(GenerativeAiInferenceClient.java:114)

#1582 "[0x453f951d 0x74dfd5cd] WebServer socket" virtual
java.base/java.lang.Object.wait0(Native Method)
java.base/java.lang.Object.wait(Object.java:366)
java.base/java.lang.Object.wait(Object.java:339)
com.oracle.bmc.http.internal.SyncFutureWaiter$Waiter.waitAndWork(SyncFutureWaiter.java:61)
com.oracle.bmc.http.internal.SyncFutureWaiter.listenForResult(SyncFutureWaiter.java:32)
com.oracle.bmc.http.internal.ClientCall.callSync(ClientCall.java:1101)
com.oracle.bmc.generativeaiinference.GenerativeAiInferenceClient.embedText(GenerativeAiInferenceClient.java:143)

[NarendraBanothu]

The pinning here is due to use of Object.wait()/Object.notifyAll() in below OCI-SDK code

java.base/java.lang.Object.wait(Object.java:339) com.oracle.bmc.http.internal.SyncFutureWaiter$Waiter.waitAndWork(SyncFutureWaiter.java:61)

https://github.com/oracle/oci-java-sdk/blob/master/bmc-common/src/main/java/com/oracle/bmc/http/internal/SyncFutureWaiter.java

public R waitAndWork() throws InterruptedException, Throwable {
synchronized (SyncFutureWaiter.this) {
while (!complete) {
Runnable task = tasks.poll();
if (task == null) {
SyncFutureWaiter.this.wait();
} else {
task.run();
}
}
....
.....
}
}

The use of Sync block and Object.wait ( SyncFutureWaiter.this.wait() ) here causes the carrier thread to be pinned in this code when running with Virtual threads with Java-21.

These code need to be replaced with a combination of ReentrantLock and Condition.await()/Condition.signalAll() , which are loom friendly and doesn't cause the carrier thread to be pinned.