Description:
When closing connections that have open Statement objects, there is an exception thrown consistently:
java.util.ConcurrentModificationException
at java.util.HashMap$HashIterator.nextEntry(HashMap.java:762)
at java.util.HashMap$KeyIterator.next(HashMap.java:798)
at com.mysql.jdbc.Connection.closeAllOpenStatements(Connection.java:2538)
at com.mysql.jdbc.Connection.close(Connection.java:1067)
It is quiet obvious from the code why this happens - any statements that are closed in the iterator are trying to modify the map we are iterating over...The patch is attached below.
How to repeat:
Open a connection
Create a Statement
Close the connection
Suggested fix:
--- ../tmp/mysql-connector-java-3.1.0-alpha/mysql-connector-java-3.1.0-alpha/com/mysql/jdbc/Connection.java Mon Feb 17 12:28:45 2003
+++ mysql-connector-java-3.1.0-alpha/com/mysql/jdbc/Connection.java Sat Nov 8 17:46:56 2003
@@ -2532,8 +2532,12 @@
*/
private void closeAllOpenStatements() throws SQLException {
SQLException postponedException = null;
+
+ // must iterate over the copy of the statements map,
+ // since each statement will try to remove itself from the map
+ // resulting in ConcurrentModificationException
- for (Iterator iter = this.openStatements.keySet().iterator();
+ for (Iterator iter = new ArrayList(this.openStatements.keySet()).iterator();
iter.hasNext();) {
Statement stmt = (Statement) iter.next();
Description: When closing connections that have open Statement objects, there is an exception thrown consistently: java.util.ConcurrentModificationException at java.util.HashMap$HashIterator.nextEntry(HashMap.java:762) at java.util.HashMap$KeyIterator.next(HashMap.java:798) at com.mysql.jdbc.Connection.closeAllOpenStatements(Connection.java:2538) at com.mysql.jdbc.Connection.close(Connection.java:1067) It is quiet obvious from the code why this happens - any statements that are closed in the iterator are trying to modify the map we are iterating over...The patch is attached below. How to repeat: Open a connection Create a Statement Close the connection Suggested fix: --- ../tmp/mysql-connector-java-3.1.0-alpha/mysql-connector-java-3.1.0-alpha/com/mysql/jdbc/Connection.java Mon Feb 17 12:28:45 2003 +++ mysql-connector-java-3.1.0-alpha/com/mysql/jdbc/Connection.java Sat Nov 8 17:46:56 2003 @@ -2532,8 +2532,12 @@ */ private void closeAllOpenStatements() throws SQLException { SQLException postponedException = null; + + // must iterate over the copy of the statements map, + // since each statement will try to remove itself from the map + // resulting in ConcurrentModificationException - for (Iterator iter = this.openStatements.keySet().iterator(); + for (Iterator iter = new ArrayList(this.openStatements.keySet()).iterator(); iter.hasNext();) { Statement stmt = (Statement) iter.next();