diff --git a/btm/src/main/java/bitronix/tm/resource/jdbc/JdbcPooledConnection.java b/btm/src/main/java/bitronix/tm/resource/jdbc/JdbcPooledConnection.java
index 2de404fd..161274e2 100644
--- a/btm/src/main/java/bitronix/tm/resource/jdbc/JdbcPooledConnection.java
+++ b/btm/src/main/java/bitronix/tm/resource/jdbc/JdbcPooledConnection.java
@@ -124,6 +124,7 @@ private synchronized void detectJdbcVersion(Connection connection) {
 
         try {
             isValidMethod = connection.getClass().getMethod("isValid", Integer.TYPE);
+            isValidMethod.setAccessible(true);
             isValidMethod.invoke(connection, DETECTION_TIMEOUT); // test invoke
             jdbcVersionDetected = 4;
             if (!poolingDataSource.isEnableJdbc4ConnectionTest()) {