Do I Need to Close ResultSets and Statements Before Closing a Connection in JDBC?

JDBC Best Practices: Closed Order of ResultSets, Statements, and Connections

It's crucial to adhere to proper JDBC resource management for optimal database performance. While closing the connection after usage is generally recommended, a common question arises regarding the necessity of separately closing ResultSets and Statements.

Question:

Given the code snippet below, is it necessary to explicitly close the ResultSet and Statement before closing the Connection?

Connection conn = null;
PreparedStatement stmt = null;
ResultSet rs = null;
try {
    conn = // Retrieve connection
    stmt = conn.prepareStatement(// Some SQL);
    rs = stmt.executeQuery();
} catch(Exception e) {
    // Error Handling
} finally {
    try { if (rs != null) rs.close(); } catch (Exception e) {};
    try { if (stmt != null) stmt.close(); } catch (Exception e) {};
    try { if (conn != null) conn.close(); } catch (Exception e) {};
}

Answer:

The code example you provided demonstrates impeccable practice. While closing the connection is essential, it's not sufficient to ensure the release of all resources.

Closing the Connection does not automatically close ResultSets or Statements. If a primitive database pooling mechanism is used and connection.close() is called, the connection will be returned to the pool, leaving unclosed ResultSets and Statements behind. This can lead to resource leaks and potential issues.

Therefore, it's imperative to close ResultSets, Statements, and Connections in the order shown in your code snippet. This ensures the proper release of all JDBC resources and prevents memory leaks.

The above is the detailed content of Do I Need to Close ResultSets and Statements Before Closing a Connection in JDBC?. For more information, please follow other related articles on the PHP Chinese website!