Fix connection leak in JdbcDatabaseDelegate

modules/jdbc/src/main/java/org/testcontainers/jdbc/JdbcDatabaseDelegate.java

@@ -6,6 +6,7 @@
 import org.testcontainers.exception.ConnectionCreationException;
 import org.testcontainers.ext.ScriptUtils;
 
+import java.sql.Connection;
 import java.sql.SQLException;
 import java.sql.Statement;
 
@@ -17,6 +18,8 @@ public class JdbcDatabaseDelegate extends AbstractDatabaseDelegate<Statement> {
 
     private JdbcDatabaseContainer container;
 
+    private Connection connection;
+
     private String queryString;
 
     public JdbcDatabaseDelegate(JdbcDatabaseContainer container, String queryString) {
@@ -27,7 +30,8 @@ public JdbcDatabaseDelegate(JdbcDatabaseContainer container, String queryString)
     @Override
     protected Statement createNewConnection() {
         try {
-            return container.createConnection(queryString).createStatement();
+            connection = container.createConnection(queryString);
+            return connection.createStatement();
         } catch (SQLException e) {
             log.error("Could not obtain JDBC connection");
             throw new ConnectionCreationException("Could not obtain JDBC connection", e);
@@ -64,6 +68,7 @@ public void execute(
     @Override
     protected void closeConnectionQuietly(Statement statement) {
         try {
+            connection.close();
             statement.close();
         } catch (Exception e) {
             log.error("Could not close JDBC connection", e);

modules/jdbc/src/test/java/org/testcontainers/jdbc/JdbcDatabaseDelegateTest.java

@@ -0,0 +1,87 @@
+package org.testcontainers.jdbc;
+
+import lombok.NonNull;
+import org.junit.Assert;
+import org.junit.Test;
+import org.mockito.Mockito;
+import org.slf4j.Logger;
+import org.testcontainers.containers.JdbcDatabaseContainer;
+import org.testcontainers.utility.DockerImageName;
+
+import java.sql.Connection;
+import java.sql.SQLException;
+import java.sql.Statement;
+import java.util.ArrayList;
+import java.util.List;
+
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class JdbcDatabaseDelegateTest {
+
+    @Test
+    public void testLeakedConnections() {
+        final JdbcDatabaseContainerStub stub = new JdbcDatabaseContainerStub(DockerImageName.parse("something"));
+        try (JdbcDatabaseDelegate delegate = new JdbcDatabaseDelegate(stub, "")) {
+            delegate.execute("foo", null, 0, false, false);
+        }
+        Assert.assertEquals(0, stub.openConnectionsList.size());
+    }
+
+    static class JdbcDatabaseContainerStub extends JdbcDatabaseContainer {
+
+        List<Connection> openConnectionsList = new ArrayList<>();
+
+        public JdbcDatabaseContainerStub(@NonNull DockerImageName dockerImageName) {
+            super(dockerImageName);
+        }
+
+        @Override
+        public String getDriverClassName() {
+            return null;
+        }
+
+        @Override
+        public String getJdbcUrl() {
+            return null;
+        }
+
+        @Override
+        public String getUsername() {
+            return null;
+        }
+
+        @Override
+        public String getPassword() {
+            return null;
+        }
+
+        @Override
+        protected String getTestQueryString() {
+            return null;
+        }
+
+        @Override
+        public boolean isRunning() {
+            return true;
+        }
+
+        @Override
+        public Connection createConnection(String queryString) throws NoDriverFoundException, SQLException {
+            final Connection connection = mock(Connection.class);
+            openConnectionsList.add(connection);
+            when(connection.createStatement()).thenReturn(mock(Statement.class));
+            connection.close();
+            Mockito.doAnswer(ignore -> openConnectionsList.remove(connection)).when(connection).close();
+            return connection;
+        }
+
+        @Override
+        protected Logger logger() {
+            return mock(Logger.class);
+        }
+
+        @Override
+        public void setDockerImageName(@NonNull String dockerImageName) {}
+    }
+}