fix: properly handle thread interrupts during gRPC channel shutdown

jdbc-core/src/main/java/com/salesforce/datacloud/jdbc/core/JdbcDriverStubProvider.java

@@ -56,13 +56,14 @@ public void close() {
         channel.shutdown();
 
         try {
-            channel.awaitTermination(5, TimeUnit.SECONDS);
-        } catch (InterruptedException e) {
-            log.error("Failed to shutdown channel within 5 seconds", e);
-        } finally {
-            if (!channel.isTerminated()) {
+            if (!channel.awaitTermination(5, TimeUnit.SECONDS)) {
+                log.warn("Channel did not terminate within 5 seconds, forcing shutdown");
                 channel.shutdownNow();
             }
+        } catch (InterruptedException e) {
+            log.warn("Channel shutdown interrupted, forcing immediate termination", e);
+            channel.shutdownNow();
+            Thread.currentThread().interrupt();
         }
     }
 }

jdbc-core/src/test/java/com/salesforce/datacloud/jdbc/core/JdbcDriverStubProviderTest.java

@@ -173,7 +173,7 @@ void shouldNotEnableRetriesWhenDisabled() {
     void callsManagedChannelCleanup() {
         val mockChannel = mock(ManagedChannel.class);
         val mockChannelBuilder = getMockChannelBuilderWithChannel(mockChannel);
-        when(mockChannel.isTerminated()).thenReturn(false, true);
+        when(mockChannel.awaitTermination(anyLong(), any(TimeUnit.class))).thenReturn(true);
 
         val stubProvider = JdbcDriverStubProvider.of(mockChannelBuilder);
         stubProvider.close();
@@ -185,10 +185,10 @@ void callsManagedChannelCleanup() {
 
     @SneakyThrows
     @Test
-    void callsManagedChannelShutdownNow() {
+    void callsManagedChannelShutdownNowOnTimeout() {
         val mockChannel = mock(ManagedChannel.class);
         val mockChannelBuilder = getMockChannelBuilderWithChannel(mockChannel);
-        when(mockChannel.isTerminated()).thenReturn(false);
+        when(mockChannel.awaitTermination(anyLong(), any(TimeUnit.class))).thenReturn(false);
 
         val stubProvider = JdbcDriverStubProvider.of(mockChannelBuilder);
         stubProvider.close();
@@ -197,4 +197,25 @@ void callsManagedChannelShutdownNow() {
         verify(mockChannel).awaitTermination(5, TimeUnit.SECONDS);
         verify(mockChannel).shutdownNow();
     }
+
+    @SneakyThrows
+    @Test
+    void handlesInterruptDuringShutdown() {
+        val mockChannel = mock(ManagedChannel.class);
+        val mockChannelBuilder = getMockChannelBuilderWithChannel(mockChannel);
+        when(mockChannel.awaitTermination(anyLong(), any(TimeUnit.class)))
+                .thenThrow(new InterruptedException("Test interruption"));
+
+        val stubProvider = JdbcDriverStubProvider.of(mockChannelBuilder);
+        stubProvider.close();
+
+        verify(mockChannel).shutdown();
+        verify(mockChannel).awaitTermination(5, TimeUnit.SECONDS);
+        verify(mockChannel).shutdownNow();
+
+        // Verify interrupt status is restored per Java best practices
+        assert Thread.currentThread().isInterrupted() : "Thread interrupt status should be restored";
+        // Clear interrupt status for other tests
+        Thread.interrupted();
+    }
 }