Handle multiple result sets (implicit cursor) with Oracle driver

Oracle driver...

... throws `SQLException` with no good reason when calling `Statement#getResultSet()`.
`SQLException` is thrown "if a database access error occurs or this method is called on a closed Statement".
https://docs.oracle.com/en/java/javase/23/docs/api/java.sql/java/sql/Statement.html#getResultSet()
https://stackoverflow.com/q/42091653/1261766

... always returns `false` from `DatabaseMetaData#supportsMultipleResultSets()` even though it apparently does.

Author: harawata

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());