oracle implicit cursor workaround

pom.xml

@@ -204,6 +204,12 @@
       <version>9.1.0</version>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <groupId>com.oracle.database.jdbc</groupId>
+      <artifactId>ojdbc8</artifactId>
+      <version>23.6.0.24.10</version>
+      <scope>test</scope>
+    </dependency>
     <dependency>
       <groupId>org.assertj</groupId>
       <artifactId>assertj-core</artifactId>
@@ -254,6 +260,12 @@
       <version>${testcontainers.version}</version>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <groupId>org.testcontainers</groupId>
+      <artifactId>oracle-free</artifactId>
+      <version>${testcontainers.version}</version>
+      <scope>test</scope>
+    </dependency>
     <!-- For javadoc link -->
     <dependency>
       <groupId>com.microsoft.sqlserver</groupId>

src/main/java/org/apache/ibatis/executor/resultset/DefaultResultSetHandler.java

@@ -247,34 +247,49 @@ public <E> Cursor<E> handleCursorResultSets(Statement stmt) throws SQLException
   }
 
   private ResultSetWrapper getFirstResultSet(Statement stmt) throws SQLException {
-    ResultSet rs = stmt.getResultSet();
-    while (rs == null) {
-      // move forward to get the first resultset in case the driver
-      // doesn't return the resultset as the first result (HSQLDB)
-      if (stmt.getMoreResults()) {
-        rs = stmt.getResultSet();
-      } else if (stmt.getUpdateCount() == -1) {
-        // no more results. Must be no resultset
-        break;
+    ResultSet rs = null;
+    SQLException e1 = null;
+
+    try {
+      rs = stmt.getResultSet();
+    } catch (SQLException e) {
+      // Oracle throws ORA-17283 for implicit cursor
+      e1 = e;
+    }
+
+    try {
+      while (rs == null) {
+        // move forward to get the first resultset in case the driver
+        // doesn't return the resultset as the first result (HSQLDB)
+        if (stmt.getMoreResults()) {
+          rs = stmt.getResultSet();
+        } else if (stmt.getUpdateCount() == -1) {
+          // no more results. Must be no resultset
+          break;
+        }
       }
+    } catch (SQLException e) {
+      throw e1 != null ? e1 : e;
     }
+
     return rs != null ? new ResultSetWrapper(rs, configuration) : null;
   }
 
   private ResultSetWrapper getNextResultSet(Statement stmt) {
     // Making this method tolerant of bad JDBC drivers
     try {
-      if (stmt.getConnection().getMetaData().supportsMultipleResultSets()) {
-        // Crazy Standard JDBC way of determining if there are more results
-        // DO NOT try to 'improve' the condition even if IDE tells you to!
-        // It's important that getUpdateCount() is called here.
-        if (!(!stmt.getMoreResults() && stmt.getUpdateCount() == -1)) {
-          ResultSet rs = stmt.getResultSet();
-          if (rs == null) {
-            return getNextResultSet(stmt);
-          } else {
-            return new ResultSetWrapper(rs, configuration);
-          }
+      // We stopped checking DatabaseMetaData#supportsMultipleResultSets()
+      // because Oracle driver (incorrectly) returns false
+
+      // Crazy Standard JDBC way of determining if there are more results
+      // DO NOT try to 'improve' the condition even if IDE tells you to!
+      // It's important that getUpdateCount() is called here.
+      if (!(!stmt.getMoreResults() && stmt.getUpdateCount() == -1)) {
+        ResultSet rs = stmt.getResultSet();
+        if (rs == null) {
+          return getNextResultSet(stmt);
+        } else {
+          return new ResultSetWrapper(rs, configuration);
         }
       }
     } catch (Exception e) {

src/test/java/org/apache/ibatis/executor/resultset/DefaultResultSetHandlerTest.java

@@ -1,5 +1,5 @@
 /*
- *    Copyright 2009-2024 the original author or authors.
+ *    Copyright 2009-2025 the original author or authors.
  *
  *    Licensed under the Apache License, Version 2.0 (the "License");
  *    you may not use this file except in compliance with the License.
@@ -92,9 +92,6 @@ void shouldRetainColumnNameCase() throws Exception {
     when(rsmd.getColumnLabel(1)).thenReturn("CoLuMn1");
     when(rsmd.getColumnType(1)).thenReturn(Types.INTEGER);
     when(rsmd.getColumnClassName(1)).thenReturn(Integer.class.getCanonicalName());
-    when(stmt.getConnection()).thenReturn(conn);
-    when(conn.getMetaData()).thenReturn(dbmd);
-    when(dbmd.supportsMultipleResultSets()).thenReturn(false); // for simplicity.
 
     final List<Object> results = fastResultSetHandler.handleResultSets(stmt);
     assertEquals(1, results.size());

src/test/java/org/apache/ibatis/submitted/oracle_implicit_cursor/Author.java

@@ -0,0 +1,83 @@
+/*
+ *    Copyright 2009-2025 the original author or authors.
+ *
+ *    Licensed under the Apache License, Version 2.0 (the "License");
+ *    you may not use this file except in compliance with the License.
+ *    You may obtain a copy of the License at
+ *
+ *       https://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    Unless required by applicable law or agreed to in writing, software
+ *    distributed under the License is distributed on an "AS IS" BASIS,
+ *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *    See the License for the specific language governing permissions and
+ *    limitations under the License.
+ */
+
+package org.apache.ibatis.submitted.oracle_implicit_cursor;
+
+import java.util.List;
+import java.util.Objects;
+
+public class Author {
+  private Integer id;
+  private String name;
+  private List<Book> books;
+
+  public Author() {
+    super();
+  }
+
+  public Author(Integer id, String name, List<Book> books) {
+    super();
+    this.id = id;
+    this.name = name;
+    this.books = books;
+  }
+
+  public Integer getId() {
+    return id;
+  }
+
+  public void setId(Integer id) {
+    this.id = id;
+  }
+
+  public String getName() {
+    return name;
+  }
+
+  public void setName(String name) {
+    this.name = name;
+  }
+
+  public List<Book> getBooks() {
+    return books;
+  }
+
+  public void setBooks(List<Book> books) {
+    this.books = books;
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(books, id, name);
+  }
+
+  @Override
+  public boolean equals(Object obj) {
+    if (this == obj) {
+      return true;
+    }
+    if (!(obj instanceof Author)) {
+      return false;
+    }
+    Author other = (Author) obj;
+    return Objects.equals(books, other.books) && Objects.equals(id, other.id) && Objects.equals(name, other.name);
+  }
+
+  @Override
+  public String toString() {
+    return "Author [id=" + id + ", name=" + name + ", books=" + books + "]";
+  }
+}

src/test/java/org/apache/ibatis/submitted/oracle_implicit_cursor/Book.java

@@ -0,0 +1,72 @@
+/*
+ *    Copyright 2009-2025 the original author or authors.
+ *
+ *    Licensed under the Apache License, Version 2.0 (the "License");
+ *    you may not use this file except in compliance with the License.
+ *    You may obtain a copy of the License at
+ *
+ *       https://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    Unless required by applicable law or agreed to in writing, software
+ *    distributed under the License is distributed on an "AS IS" BASIS,
+ *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *    See the License for the specific language governing permissions and
+ *    limitations under the License.
+ */
+
+package org.apache.ibatis.submitted.oracle_implicit_cursor;
+
+import java.util.Objects;
+
+public class Book {
+  private Integer id;
+  private String name;
+
+  public Book() {
+    super();
+  }
+
+  public Book(Integer id, String name) {
+    super();
+    this.id = id;
+    this.name = name;
+  }
+
+  public Integer getId() {
+    return id;
+  }
+
+  public void setId(Integer id) {
+    this.id = id;
+  }
+
+  public String getName() {
+    return name;
+  }
+
+  public void setName(String name) {
+    this.name = name;
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(id, name);
+  }
+
+  @Override
+  public boolean equals(Object obj) {
+    if (this == obj) {
+      return true;
+    }
+    if (!(obj instanceof Book)) {
+      return false;
+    }
+    Book other = (Book) obj;
+    return Objects.equals(id, other.id) && Objects.equals(name, other.name);
+  }
+
+  @Override
+  public String toString() {
+    return "Book [id=" + id + ", name=" + name + "]";
+  }
+}

src/test/java/org/apache/ibatis/submitted/oracle_implicit_cursor/Mapper.java

@@ -0,0 +1,28 @@
+/*
+ *    Copyright 2009-2025 the original author or authors.
+ *
+ *    Licensed under the Apache License, Version 2.0 (the "License");
+ *    you may not use this file except in compliance with the License.
+ *    You may obtain a copy of the License at
+ *
+ *       https://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    Unless required by applicable law or agreed to in writing, software
+ *    distributed under the License is distributed on an "AS IS" BASIS,
+ *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *    See the License for the specific language governing permissions and
+ *    limitations under the License.
+ */
+package org.apache.ibatis.submitted.oracle_implicit_cursor;
+
+import java.util.List;
+
+public interface Mapper {
+
+  List<Author> selectImplicitCursors_Statement();
+
+  List<Author> selectImplicitCursors_Prepared();
+
+  List<Author> selectImplicitCursors_Callable();
+
+}

src/test/java/org/apache/ibatis/submitted/oracle_implicit_cursor/OracleImplicitCursorTest.java

@@ -0,0 +1,78 @@
+/*
+ *    Copyright 2009-2025 the original author or authors.
+ *
+ *    Licensed under the Apache License, Version 2.0 (the "License");
+ *    you may not use this file except in compliance with the License.
+ *    You may obtain a copy of the License at
+ *
+ *       https://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    Unless required by applicable law or agreed to in writing, software
+ *    distributed under the License is distributed on an "AS IS" BASIS,
+ *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *    See the License for the specific language governing permissions and
+ *    limitations under the License.
+ */
+package org.apache.ibatis.submitted.oracle_implicit_cursor;
+
+import static org.junit.jupiter.api.Assertions.assertIterableEquals;
+
+import java.util.List;
+import java.util.function.Function;
+
+import org.apache.ibatis.BaseDataTest;
+import org.apache.ibatis.mapping.Environment;
+import org.apache.ibatis.session.Configuration;
+import org.apache.ibatis.session.SqlSession;
+import org.apache.ibatis.session.SqlSessionFactory;
+import org.apache.ibatis.session.SqlSessionFactoryBuilder;
+import org.apache.ibatis.testcontainers.OracleTestContainer;
+import org.apache.ibatis.transaction.jdbc.JdbcTransactionFactory;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Tag;
+import org.junit.jupiter.api.Test;
+
+@Tag("TestcontainersTests")
+class OracleImplicitCursorTest {
+
+  private static SqlSessionFactory sqlSessionFactory;
+
+  @BeforeAll
+  static void setUp() throws Exception {
+    Configuration configuration = new Configuration();
+    Environment environment = new Environment("development", new JdbcTransactionFactory(),
+        OracleTestContainer.getUnpooledDataSource());
+    configuration.setEnvironment(environment);
+    configuration.addMapper(Mapper.class);
+    sqlSessionFactory = new SqlSessionFactoryBuilder().build(configuration);
+
+    BaseDataTest.runScript(sqlSessionFactory.getConfiguration().getEnvironment().getDataSource(),
+        "org/apache/ibatis/submitted/oracle_implicit_cursor/CreateDB.sql");
+  }
+
+  @Test
+  void shouldImplicitCursors_Statement() {
+    doTest(Mapper::selectImplicitCursors_Statement);
+  }
+
+  @Test
+  void shouldImplicitCursors_Prepared() {
+    doTest(Mapper::selectImplicitCursors_Prepared);
+  }
+
+  @Test
+  void shouldImplicitCursors_Callable() {
+    doTest(Mapper::selectImplicitCursors_Callable);
+  }
+
+  private void doTest(Function<Mapper, List<Author>> query) {
+    try (SqlSession sqlSession = sqlSessionFactory.openSession()) {
+      Mapper mapper = sqlSession.getMapper(Mapper.class);
+      List<Author> authors = query.apply(mapper);
+      assertIterableEquals(
+          List.of(new Author(1, "John", List.of(new Book(1, "C#"), new Book(2, "Python"), new Book(5, "Ruby"))),
+              new Author(2, "Jane", List.of(new Book(3, "SQL"), new Book(4, "Java")))),
+          authors);
+    }
+  }
+}