Allow to use empty typeMap on Connection

src/main/java/org/duckdb/DuckDBConnection.java

@@ -20,6 +20,7 @@
 import java.sql.Savepoint;
 import java.sql.Statement;
 import java.sql.Struct;
+import java.util.HashMap;
 import java.util.Map;
 import java.util.Properties;
 import java.util.concurrent.Executor;
@@ -257,10 +258,22 @@ public CallableStatement prepareCall(String sql, int resultSetType, int resultSe
     }
 
     public Map<String, Class<?>> getTypeMap() throws SQLException {
-        throw new SQLFeatureNotSupportedException("getTypeMap");
+        if (isClosed()) {
+            throw new SQLException("Connection was closed");
+        }
+        return new HashMap<>();
     }
 
     public void setTypeMap(Map<String, Class<?>> map) throws SQLException {
+        if (isClosed()) {
+            throw new SQLException("Connection was closed");
+        }
+        if (map != null && (map instanceof java.util.HashMap)) {
+            // we return an empty Hash map if the user gives this back make sure we accept it.
+            if (map.isEmpty()) {
+                return;
+            }
+        }
         throw new SQLFeatureNotSupportedException("setTypeMap");
     }
 

src/test/java/org/duckdb/TestDuckDBJDBC.java

@@ -4793,6 +4793,19 @@ public static void test_client_config_retained_on_dup() throws Exception {
         }
     }
 
+    public static void test_empty_typemap_allowed() throws Exception {
+        try (Connection conn = DriverManager.getConnection(JDBC_URL)) {
+            Map<String, Class<?>> defaultMap = conn.getTypeMap();
+            assertEquals(defaultMap.size(), 0);
+            // check empty not throws
+            conn.setTypeMap(new HashMap<>());
+            // check custom map throws
+            Map<String, Class<?>> customMap = new HashMap<>();
+            customMap.put("foo", TestDuckDBJDBC.class);
+            assertThrows(() -> { conn.setTypeMap(customMap); }, SQLException.class);
+        }
+    }
+
     public static void main(String[] args) throws Exception {
         String arg1 = args.length > 0 ? args[0] : "";
         final int statusCode;