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Using resultset data after closing the connection

I'm trying to write a small code snippet where I need to get some data from a database and then process the result in some other java file. I tried writing a program and the execution for the same was failing with error "Cannot access resultset as the connection was already closed".
Is there any way can we store the result fetched from database some where (Ex.some arraylist) and use it for computation after closing the connection? If yes, can someone please explain it with example?
Slightly handicapped since I'm new to it.
Class A {
public Map<String, Object> loadDat(int acc,Map<String,Object> result)
throws Exception {
Class.forName("com.teradata.jdbc.TeraDriver");
Connection conn = DriverManager.getConnection(connectionString, user, password);
query = "select * from mytable where id="+acc;
PreparedStatement stmt = conn.prepareStatement(query);
ResultSet rs=stmt.executeQuery();
result.put(" Result", rs) ;
return result;
}
}

In general,
don't code JDBC database access by hand.
Libraries already exist that do all the low level JDBC handling now and
they do it correctly.
You will never do it better than an one of the mature,
open source projects already do it.
Instead,
learn and use something like MyBatis.
If you use Spring,
here is a link to the Mybatis-Spring project.
MyBatis conceals all of the data conversion and JDBC junk.
Instead, you define your query in a simple XML file and receive a List
as the result of a query.

Just to add to #DwB's answer that is correct.
You can 1) retrieve all rows from your query into a Java List, 2) then close the connection, and 3) then use the Java List in another class (for further processing).
If you close the connection after retrieving only part of the result set, you'll lose the rest of it and will receive the error you mention. Don't do it this way.

Will ResultSet be updated with the underlying database?

Before I explain my problem I would like to say that I know the basics of JDBC but not really used to it.
I am using an updatable result set to hold data from 2 different tables, as in the following sample code:
searchQry = "SELECT ct.CustomerName, ct.Email, ct.PhoneNo, ot.ItemName
FROM CUSTOMER_TABLE ct JOIN ORDER_Table ot
ON ct.OrderID = ot.OrderID";
prestmt = dbcon.prepareStatement(searchQry, ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE);
uprs = prestmt.executeQuery();
uprs.updateLong("ut.PhoneNo", 7240987456L);
uprs.updateString("otItemName", "GTA5");
uprs.updateRow();
I would like to know if I will update the database from somewhere else (not using the same result set object) while the result set, upsr, connected to the database, whether uprs will get updated with it or it will throw an error or it will go with the old data itself. Sorry if it a newbie question but I can't really test that on my DB without knowing the outcomes and safe measures.
Please, suggest me if there is any better way to update the underlining db along with the data in the ResultSet without having any transaction issues when changing from different places.
Using:
Oracle Database for JDBC connection.

How to enter SQL instruction in controller with play 2 and java

I'm developing a web application with Play 2.1.0 and programming it with Java and I need to have access to data already saved in a DB to modify them.
I tried to create a new instance without the new operator and reference it to my object saved in the database, but even if there is no pointer error, it won't change values of attributes. I couldn't figure out why, so I've decided to enter SQL queries directly.
Same thing, it does not seems to have any mistake, but it won't change anything... I think this comes from a bad link to the database :
Here is my code in application.java :
public static Result modifyQuestionnaire(Long id) throws SQLException {
Statement stmt = null;
Connection con = DB.getConnection();
try {
stmt = con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE);
String query = "SELECT * FROM WOQ.questionnaire WHERE id=id";
ResultSet uprs = stmt.executeQuery(query);
uprs.updateString("name", "baba");
uprs.updateRow();
} catch(Exception e) {
e.printStackTrace();
} finally {
if (stmt!=null) {
stmt.close();
}
}
return redirect(routes.Application.questionnaire(id));
}
And I also try to enter an UPDATE query directly, still the same..
I've looked everywhere and did not find any solution (except Anorm but it seems to work with Scala language)
Btw, if anyone knows a solution with a second instance that refers to the same object (it seems possible but as I say, there is no error but no actions neither), it's fine for me.

Huh, you showed as that you are trying to create totally new connection, so I supposed, that you don't want to use Ebean, but in case when you are already use it, you can just use its methods for the task:
(copied) There are some options in Ebean's API, so you should check it and choose one:
Update<T> - check in the sample for #NamedUpdates annotation
Ebean.createUpdate(beanType, updStatement)
SqlUpdate - you can just perform raw SQL update, without need for giving the entity type

how to print Statement (CallableStatement) in Java?

How can I print this OracleCallableStatement ?
ocstmt = (OracleCallableStatement) connection.prepareCall("{?= call
package.method(id => ?, name=>?)}");
ocstmt.registerOutParameter(1, OracleTypes.CURSOR);
ocstmt.setInt(2, obj.getId());
ocstmt.setString(3, obj.getName());
ocstmt.execute();
resultSet = ocstmt.getCursor(1);
What I mean is how can I know that what query goes to the database, how can I print the query? because sometimes it gives me error like "Wrong type" that is why I want to look at this query

Are you using log4j?
If so, add loggers for sql like below.
log4j.logger.java.sql.Connection=DEBUG
log4j.logger.java.sql.Statement=DEBUG
log4j.logger.java.sql.PreparedStatement=DEBUG
log4j.logger.java.sql.ResultSet=DEBUG
If you are using a ORM framework such as ibatis, you could add additional logger like below.
log4j.logger.com.ibatis.sqlmap.engine.impl.SqlMapClientDelegate=DEBUG

Yes, you can do this. You can either wrap your callable statement in a proxy that can substitute the actual values when you print it (and show the sql), or hunt around for a driver that has a meaningful toString. javaworld article There is also p6spy, and others.
Stored procedures are harder, but still doable.

You can't get the SQL by printing the Statement.
Is the example you posted one of the "sometimes" that triggers the error?
Why do you have to case this to an OracleCallableStatement? What part of the call is not the standard CallableStatement?

In general, use myObject.toString() to see what it prints. You may or may not be able to see the full query though. If you can't get it to go, the first thing that I would look at is the API documentation(javadocs for that Oracle library or driver that you're using)

I'm not sure if I understand the question, but it seems like you want to see this:
String sql = "{?= call package.method(id => ?, name=>?)}";
System.out.println(sql);
ocstmt = (OracleCallableStatement) connection.prepareCall(sql);
...

It's possible to use proxy jdbc driver to log all jdbc database actions.
this driver can prints all statements with values and all results.

My solution is use ProxyDataSourceBuilder(use it in Spring Boot project).
#Bean
public DataSource dataSource() {
SLF4JQueryLoggingListener loggingListener = new SLF4JQueryLoggingListener();
return ProxyDataSourceBuilder
.create(datasource)
.listener(loggingListener)
.build();
}
...
#Autowired
private DataSource dataSource;
Connection connection = dataSource.getConnection();
ocstmt = (OracleCallableStatement) connection.prepareCall("{?= call
package.method(id => ?, name=>?)}");
And just turn on logging in application.yml:
logging:
level:
net.ttddyy.dsproxy.listener.logging: debug

Try
> java -classpath ojdbc8.jar oracle.jdbc.driver.OracleSql false false "<your sql here>"
That will print the SQL that the driver sends to the database, among other things. This is not documented nor supported, but it's been around forever.

I thought it might be useful if you are looking whether executed query has value or not
System.out.println("value : "+CallableStatement.execute());
i.e The "false" returned by "CallableStatement.execute()" means that the JDBC statement didn't read any rows, (so there's no ResultSet to read). This is what you'd expect, as stored procedures don't directly return ResultSets, they only return values for any OUT or INOUT parameters.

Specifying a variable name in QUERY WHERE clause in JDBC

Could someone please give me a link on how to create a query in JDBC that gets a variable name in the WHERE statement, or write an example, to be more specific, my code looks something like this:
private String getLastModified(String url) {
String lastModified = null;
ResultSet resultSet;
String query = "select LastModified from CacheTable where " +
" URL.equals(url)";
try {
resultSet = sqlStatement.executeQuery(query);
}
Now I need the syntax that enables me to return a ResultSet object where URL in the cacheTable equals url from the method's argument.
thanks

The easiest way would be
String query = "select LastModified from CacheTable where url = '" + url +"'";
You should use bind variables though:
String query = "select LastModified from CacheTable where url = ?";
prepStmt = conn.prepareStatement(query);
prepStmt.setString(1, url);
rs = prepStmt.executeQuery();

To take it one step further you should really use DBUtils from apache-commons or Sping JDBC framework. A lot of JDBC work is mundane and error prone due to the number of steps involved with it. Both links have working examples for you to get started.
These helper libraries will make your life much more comfortable :-).

To clear a misconception: JDBC and SQL are two entirely different things. Databases only understand the SQL language. It's a (semi)standard which you can learn here. JDBC is just a Java API which enables you to execute SQL language using Java code. Nothing less, nothing more. JDBC is not a Java way of writing SQL language or so. It's just the messenger between Java code and the database. You can learn JDBC here.
That said, yes, the PreparedStatement is the way to go to set values in a SQL query. It not only eases setting fullworthy Java objects in a SQL string using the setXXX() methods, but it also saves you from SQL injection attacks.