Fix socket leak in Java Cloud Debugger (external version only)

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=111476982

src/agent/internals/src/main/java/com/google/devtools/cdbg/debuglets/java/GcpHubClient.java

@@ -386,6 +386,8 @@ public ListActiveBreakpointsResult listActiveBreakpoints() throws Exception {
         response = gson.fromJson(reader, ListActiveBreakpointsResponse.class);
       } catch (IOException e) {
         if (connection.get().getResponseCode() == 409) {
+          // We have to close the error stream. Otherwise the network connection leaks.
+          connection.get().getErrorStream().close();
           return LIST_ACTIVE_BREAKPOINTS_TIMEOUT;
         }
 
@@ -445,6 +447,8 @@ public void transmitBreakpointUpdate(String format, String breakpointId, byte[]
       try {
         connection.get().getInputStream().close();
       } catch (IOException e) {
+        // We always call readErrorStream to close the error stream to avoid socket leak.
+        String errorResponse = readErrorStream(connection.get());
         int responseCode = connection.get().getResponseCode();
 
         // We consider all application errors (5xx) and timeout (408) to be transient errors
@@ -454,7 +458,7 @@ public void transmitBreakpointUpdate(String format, String breakpointId, byte[]
           // There is no point in retrying the transmission. It will fail.
           warnfmt(e, "Failed to transmit breakpoint update, debuggee: %s, breakpoint ID: %s, "
               + "response: %s\n%s", debuggeeId, breakpointId,
-              connection.get().getResponseMessage(), readErrorStream(connection.get()));
+              connection.get().getResponseMessage(), errorResponse);
           return;
         }