fixup! Fix ChannelFetcher memory leak

Author: trask

core/src/main/java/com/microsoft/applicationinsights/TelemetryClient.java

@@ -54,6 +54,7 @@ public class TelemetryClient {
     private volatile TelemetryContext context;
     private TelemetryChannel channel;
 
+    private static final Object TELEMETRY_STOP_HOOK_LOCK = new Object();
     private static final Object TELEMETRY_CONTEXT_LOCK = new Object();
 
     private static AtomicLong generateCounter = new AtomicLong(0);
@@ -66,6 +67,10 @@ public TelemetryClient(TelemetryConfiguration configuration) {
             configuration = TelemetryConfiguration.getActive();
         }
 
+        synchronized (TELEMETRY_STOP_HOOK_LOCK) {
+            SDKShutdownActivity.INSTANCE.register(configuration.getChannel());
+        }
+
         this.configuration = configuration;
     }
 
@@ -497,7 +502,6 @@ public void flush() {
     TelemetryChannel getChannel() {
         if (this.channel == null) {
             this.channel = configuration.getChannel();
-            SDKShutdownActivity.INSTANCE.register(this.channel);
         }
 
         return this.channel;

core/src/main/java/com/microsoft/applicationinsights/internal/shutdown/SDKShutdownActivity.java

@@ -22,6 +22,7 @@
 package com.microsoft.applicationinsights.internal.shutdown;
 
 import java.io.Closeable;
+import java.util.HashMap;
 import java.util.List;
 import java.util.ArrayList;
 import java.util.Map;
@@ -53,7 +54,7 @@ public enum SDKShutdownActivity {
     private static class SDKShutdownAction implements Runnable {
         private boolean stopped = false;
 
-        private final Map<TelemetryChannel, Boolean> channels = new WeakHashMap<>();
+        private final Map<TelemetryChannel, Boolean> channels = new HashMap<>();
         @Deprecated
         private final List<ChannelFetcher> fetchers = new ArrayList<ChannelFetcher>();
         private final List<Stoppable> stoppables = new ArrayList<Stoppable>();
@@ -151,8 +152,9 @@ private void stopChannel(TelemetryChannel channelToStop) {
                 throw td;
             } catch (Throwable t) {
                 try {
-                    InternalLogger.INSTANCE.error("Failed to stop channel: '%s'", t.toString());
-                    InternalLogger.INSTANCE.trace("Stack trace generated is %s", ExceptionUtils.getStackTrace(t));
+                    if (InternalLogger.INSTANCE.isErrorEnabled()) {
+                        InternalLogger.INSTANCE.error("Failed to stop channel: '%s'", ExceptionUtils.getStackTrace(t));
+                    }
                 } catch (ThreadDeath td) {
                     throw td;
                 } catch (Throwable t2) {