How to properly keep a DB connection from a Connection Pool opened in JBoss

Question

I\'m using JBoss AS 7.1 as a server and I have my DataSource configured with pooling. I\'m quite new to this so please excuse any rookie mistakes... after all I\'m here to l

Answer 1

How do I properly keep my connection opened?

You must not do that, let the connection pool handle this.

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Behind the scenes, the connection pool will keep a bunch of database connections to the database engine (MySQL, Oracle, SQL Server... depends how you configure it) in SLEEPING state. When you execute this code:

//avoiding all the particular exceptions just for code simplicity purposes...
//in real world applications, you must handle each of these exceptions
public Connection getConnection() throws Exception {
    ctx = new InitialContext();
    ds1 = (javax.sql.DataSource) ctx.lookup(strDSName1);
    return ds1.getConnection();
}

You're asking to the connection pool to retrieve one of these connections available. The connection pool will give you a database connection (if available) and let you use it as long as you want. Then you use it wherever you want/need and close it:

public void foo() throws Exception {
    Connection connection = getConnection();
    //do what you want/need...

    //in the end, you close the connection
    //this is A MUST!
    connection.close();
}

When executing connection.close() from a connection retrieved by the connection pool, you're not closing the physical database connection but notifying the connection pool this specific database connection must return to the SLEEPING state.

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Some advices from the explanation:

• You must not try to keep the connection alive, that's connection pool's job.
• You must not try to store the connections in any cache-like structure, that's connection pool's job.
• You must retrieve a java.sql.Connection in the shortest scope you will need it. Once you have used it, close it.