Remove JSR-305 ThreadSafe annotation and replace with JavaDoc where appropriate

Author: Kainsin

api/src/main/java/io/grpc/Channel.java

@@ -16,7 +16,6 @@
 
 package io.grpc;
 
-import javax.annotation.concurrent.ThreadSafe;
 
 /**
  * A virtual connection to a conceptual endpoint, to perform RPCs. A channel is free to have zero or
@@ -29,8 +28,9 @@
  * implementations using {@link ClientInterceptor}. It is expected that most application
  * code will not use this class directly but rather work with stubs that have been bound to a
  * Channel that was decorated during application initialization.
+ * 
+ * <p>This is thread-safe and should be considered for the errorprone ThreadSafe annotation in the future
  */
-@ThreadSafe
 public abstract class Channel {
   /**
    * Create a {@link ClientCall} to the remote operation specified by the given

api/src/main/java/io/grpc/ChannelLogger.java

@@ -16,15 +16,15 @@
 
 package io.grpc;
 
-import javax.annotation.concurrent.ThreadSafe;
 
 /**
  * A Channel-specific logger provided by GRPC library to {@link LoadBalancer} implementations.
  * Information logged here goes to <strong>Channelz</strong>, and to the Java logger of this class
  * as well.
+ * 
+ * <p>This is thread-safe and should be considered for the errorprone ThreadSafe annotation in the future
  */
 @ExperimentalApi("https://github.com/grpc/grpc-java/issues/5029")
-@ThreadSafe
 public abstract class ChannelLogger {
   /**
    * Log levels.  See the table below for the mapping from the ChannelLogger levels to Channelz

api/src/main/java/io/grpc/ClientInterceptor.java

@@ -16,7 +16,6 @@
 
 package io.grpc;
 
-import javax.annotation.concurrent.ThreadSafe;
 
 /**
  * Interface for intercepting outgoing calls before they are dispatched by a {@link Channel}.
@@ -37,8 +36,9 @@
  * without completing the previous ones first. Refer to the
  * {@link io.grpc.ClientCall.Listener ClientCall.Listener} docs for more details regarding thread
  * safety of the returned listener.
+ * 
+ * <p>This is thread-safe and should be considered for the errorprone ThreadSafe annotation in the future
  */
-@ThreadSafe
 public interface ClientInterceptor {
   /**
    * Intercept {@link ClientCall} creation by the {@code next} {@link Channel}.

api/src/main/java/io/grpc/ClientStreamTracer.java

@@ -19,13 +19,13 @@
 import static com.google.common.base.Preconditions.checkNotNull;
 
 import com.google.common.base.MoreObjects;
-import javax.annotation.concurrent.ThreadSafe;
 
 /**
  * {@link StreamTracer} for the client-side.
+ * 
+ * <p>This is thread-safe and should be considered for the errorprone ThreadSafe annotation in the future
  */
 @ExperimentalApi("https://github.com/grpc/grpc-java/issues/2861")
-@ThreadSafe
 public abstract class ClientStreamTracer extends StreamTracer {
   /**
    * Indicates how long the call was delayed, in nanoseconds, due to waiting for name resolution

api/src/main/java/io/grpc/CompressorRegistry.java

@@ -22,13 +22,13 @@
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
 import javax.annotation.Nullable;
-import javax.annotation.concurrent.ThreadSafe;
 
 /**
  * Encloses classes related to the compression and decompression of messages.
+ * 
+ * <p>This is thread-safe and should be considered for the errorprone ThreadSafe annotation in the future
  */
 @ExperimentalApi("https://github.com/grpc/grpc-java/issues/1704")
-@ThreadSafe
 public final class CompressorRegistry {
   private static final CompressorRegistry DEFAULT_INSTANCE = new CompressorRegistry(
       new Codec.Gzip(),

api/src/main/java/io/grpc/DecompressorRegistry.java

@@ -27,13 +27,13 @@
 import java.util.Map;
 import java.util.Set;
 import javax.annotation.Nullable;
-import javax.annotation.concurrent.ThreadSafe;
 
 /**
  * Encloses classes related to the compression and decompression of messages.
+ * 
+ * <p>This is thread-safe and should be considered for the errorprone ThreadSafe annotation in the future
  */
 @ExperimentalApi("https://github.com/grpc/grpc-java/issues/1704")
-@ThreadSafe
 public final class DecompressorRegistry {
   static final Joiner ACCEPT_ENCODING_JOINER = Joiner.on(',');
 

api/src/main/java/io/grpc/HandlerRegistry.java

@@ -19,12 +19,12 @@
 import java.util.Collections;
 import java.util.List;
 import javax.annotation.Nullable;
-import javax.annotation.concurrent.ThreadSafe;
 
 /**
  * Registry of services and their methods used by servers to dispatching incoming calls.
+ * 
+ * <p>This is thread-safe and should be considered for the errorprone ThreadSafe annotation in the future
  */
-@ThreadSafe
 public abstract class HandlerRegistry {
 
   /**

api/src/main/java/io/grpc/LoadBalancer.java

@@ -32,7 +32,6 @@
 import javax.annotation.Nullable;
 import javax.annotation.concurrent.Immutable;
 import javax.annotation.concurrent.NotThreadSafe;
-import javax.annotation.concurrent.ThreadSafe;
 
 /**
  * A pluggable component that receives resolved addresses from {@link NameResolver} and provides the
@@ -447,10 +446,11 @@ public void requestConnection() {}
   /**
    * The main balancing logic.  It <strong>must be thread-safe</strong>. Typically it should only
    * synchronize on its own state, and avoid synchronizing with the LoadBalancer's state.
+   * 
+   * <p>This is thread-safe and should be considered for the errorprone ThreadSafe annotation in the future
    *
    * @since 1.2.0
    */
-  @ThreadSafe
   @ExperimentalApi("https://github.com/grpc/grpc-java/issues/1771")
   public abstract static class SubchannelPicker {
     /**
@@ -1031,8 +1031,8 @@ public String toString() {
    * Provides essentials for LoadBalancer implementations.
    *
    * @since 1.2.0
+   * <p>This is thread-safe and should be considered for the errorprone ThreadSafe annotation in the future
    */
-  @ThreadSafe
   @ExperimentalApi("https://github.com/grpc/grpc-java/issues/1771")
   public abstract static class Helper {
     /**
@@ -1552,8 +1552,8 @@ public interface SubchannelStateListener {
    * Factory to create {@link LoadBalancer} instance.
    *
    * @since 1.2.0
+   * <p>This is thread-safe and should be considered for the errorprone ThreadSafe annotation in the future
    */
-  @ThreadSafe
   @ExperimentalApi("https://github.com/grpc/grpc-java/issues/1771")
   public abstract static class Factory {
     /**

api/src/main/java/io/grpc/LoadBalancerRegistry.java

@@ -30,16 +30,16 @@
 import java.util.logging.Level;
 import java.util.logging.Logger;
 import javax.annotation.Nullable;
-import javax.annotation.concurrent.ThreadSafe;
 
 /**
  * Registry of {@link LoadBalancerProvider}s.  The {@link #getDefaultRegistry default instance}
  * loads providers at runtime through the Java service provider mechanism.
- *
+ * 
+ * <p>This is thread-safe and should be considered for the errorprone ThreadSafe annotation in the future
+ * 
  * @since 1.17.0
  */
 @ExperimentalApi("https://github.com/grpc/grpc-java/issues/1771")
-@ThreadSafe
 public final class LoadBalancerRegistry {
   private static final Logger logger = Logger.getLogger(LoadBalancerRegistry.class.getName());
   private static LoadBalancerRegistry instance;

api/src/main/java/io/grpc/ManagedChannel.java

@@ -17,12 +17,12 @@
 package io.grpc;
 
 import java.util.concurrent.TimeUnit;
-import javax.annotation.concurrent.ThreadSafe;
 
 /**
  * A {@link Channel} that provides lifecycle management.
+ * 
+ * <p>This is thread-safe and should be considered for the errorprone ThreadSafe annotation in the future
  */
-@ThreadSafe
 public abstract class ManagedChannel extends Channel {
   /**
    * Initiates an orderly shutdown in which preexisting calls continue but new calls are immediately