[DBCP-412] dbcp2.PoolableConnection.close raises NullPointerException

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 2.0
• Fix Version/s: 2.1
• Labels: NullPointerException PoolableConnection

Environment

Mac OSX, Java 7, SQLAzure

• Assignee: Unassigned
• Reporter: Davide Caroselli
• Created: 03/Apr/14 10:10
• Updated: 24/Feb/15 03:23
• Resolved: 14/Feb/15 00:04

Description

I found a critical error while closing a PoolableConnection.
Here's the code to reproduce the bug (largely copied from the example shown in the Apache DBCP site):

PoolingDataSourceExample2.java

public static void main(String[] args) throws Throwable {
    Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
    DataSource dataSource = setupDataSource(jdbcUrl);

    Connection connection = null;
    PreparedStatement statement = null;
    ResultSet result = null;

    try {
        connection = dataSource.getConnection();
        statement = connection.prepareStatement("SELECT 1");
        result = statement.executeQuery();
    } finally {
        result.close();
        statement.close();
        connection.close();
    }
}

public static DataSource setupDataSource(String connectURI) {
    ConnectionFactory connectionFactory = new DriverManagerConnectionFactory(connectURI, null);
    PoolableConnectionFactory poolableConnectionFactory = new PoolableConnectionFactory(connectionFactory, null);
    ObjectPool<PoolableConnection> connectionPool = new GenericObjectPool<>(poolableConnectionFactory);
    PoolingDataSource<PoolableConnection> dataSource = new PoolingDataSource<>(connectionPool);

    return dataSource;
}

When the code tries to close the connection (in the final block), an exception is raised:

PoolingDataSourceExample2.java

Exception in thread "main" java.lang.NullPointerException
	at org.apache.commons.dbcp2.PoolableConnection.close(PoolableConnection.java:151)
	at org.apache.commons.dbcp2.DelegatingConnection.closeInternal(DelegatingConnection.java:235)
	at org.apache.commons.dbcp2.DelegatingConnection.close(DelegatingConnection.java:218)
	at org.apache.commons.dbcp2.PoolingDataSource$PoolGuardConnectionWrapper.close(PoolingDataSource.java:212)
	at dbcp.PoolingDataSourceExample2.closeQuietly(PoolingDataSourceExample2.java:64)
	at dbcp.PoolingDataSourceExample2.main(PoolingDataSourceExample2.java:43)

As I can see, the problem is the "_pool" variable inside PoolableConnection but I could not find any solution.