Can we execute some queries while traversing resultset in java

Question

I am trying to implement a task in java using JDBC like Stored Procedure in SQL. In SQL, when we write cursor, first we execute select query and then fetching the records we

Answer 1

I would restructure your flow. Primarily, don't try and reuse the same Statement object to execute a new query. When I try that using the PostgreSQL driver, for example, I readily get an exception, "This ResultSet is closed."

Instead, rewrite it to something like this:

Connection conn = DriverManager.getConnection(...);
Statement outerStatement = conn.createStatement();
ResultSet outerResultSet = outerStatement.executeQuery("...");

while (outerResultSet.next()) {
    Statement innerStatement = conn.createStatement();
    ResultSet innerResultSet = innerStatement.executeQuery("...");
    while (innerResultSet.next()) {
        // ...
    }
    innerResultSet.close();
    innerStatement.close();
}
outerResultSet.close();
outerStatement.close();
conn.close();

Of course, surround with try-catch-finally as needed.