fix shutdown

Author: Neenu1995

java-bigquery-jdbc/src/main/java/com/google/cloud/bigquery/jdbc/BigQueryConnection.java

@@ -964,14 +964,38 @@ private void closeImpl() throws SQLException {
 
       if (this.metadataExecutor != null) {
         this.metadataExecutor.shutdown();
-        this.metadataExecutor.awaitTermination(10, TimeUnit.SECONDS);
-        this.metadataExecutor.shutdownNow();
       }
-
       if (this.queryExecutor != null) {
         this.queryExecutor.shutdown();
-        this.queryExecutor.awaitTermination(10, TimeUnit.SECONDS);
-        this.queryExecutor.shutdownNow();
+      }
+
+      boolean interrupted = false;
+
+      if (this.metadataExecutor != null) {
+        try {
+          if (!this.metadataExecutor.awaitTermination(10, TimeUnit.SECONDS)) {
+            this.metadataExecutor.shutdownNow();
+          }
+        } catch (InterruptedException e) {
+          this.metadataExecutor.shutdownNow();
+          interrupted = true;
+        }
+      }
+
+      if (this.queryExecutor != null) {
+        try {
+          if (!this.queryExecutor.awaitTermination(10, TimeUnit.SECONDS)) {
+            this.queryExecutor.shutdownNow();
+          }
+        } catch (InterruptedException e) {
+          this.queryExecutor.shutdownNow();
+          interrupted = true;
+        }
+      }
+
+      if (interrupted) {
+        Thread.currentThread().interrupt();
+        throw new InterruptedException("Interrupted awaiting executor termination");
       }
     } catch (ConcurrentModificationException ex) {
       throw new BigQueryJdbcException("Concurrent modification during close", ex);

java-bigquery-jdbc/src/main/java/com/google/cloud/bigquery/jdbc/DataSource.java

@@ -1413,6 +1413,11 @@ private static void validateNonNegative(long val, String propertyName) {
     }
   }
 
+  /**
+   * Validates that a property value is greater than or equal to a minimum threshold.
+   * For thread pools, a minimum of 2 is enforced to ensure there are enough threads
+   * to handle concurrent coordination and avoid deadlock or thread starvation.
+   */
   private static void validateMin(long val, long min, String propertyName) {
     if (val < min) {
       throw new BigQueryJdbcRuntimeException(