Java Connection in LKM

Question

Hi all,
I am trying to add a command at LKM ,so that it establish a connection to the source database and retrieve values from a table.
i have added this at Command on Source
<@
import java.sql.*;
import java.lang.*;
Connection myCon = odiRef.getJDBCConnection("SRC");
Statement myStmt = myCon.createStatement();
ResultSet myRs = myStmt.executeQuery("select count(*) FROM SAMPLE");
myRs.next();
String myString = myRs.getString(1);
System.out.println(myString);
@>
Now the SRC is GLOBAl context.while executing i want to it to be dynamic based on current running physical data server
when i execute the interface it gives me the following error.
java.lang.Exception: The application script threw an exception: java.lang.NullPointerException: Null Pointer in Method Invocation BSF info: HCL at line: 0 column: columnNo
     at com.sunopsis.dwg.codeinterpretor.a.a(a.java)
     at com.sunopsis.dwg.dbobj.SnpSessTaskSql.codeInterpretation(SnpSessTaskSql.java)
     at com.sunopsis.dwg.dbobj.SnpSessTaskSql.execIntegratedFunction(SnpSessTaskSql.java)
     at com.sunopsis.dwg.dbobj.SnpSessTaskSql.treatTaskTrt(SnpSessTaskSql.java)
     at com.sunopsis.dwg.dbobj.SnpSessTaskSqlC.treatTaskTrt(SnpSessTaskSqlC.java)
     at com.sunopsis.dwg.dbobj.SnpSessTaskSql.treatTask(SnpSessTaskSql.java)
     at com.sunopsis.dwg.dbobj.SnpSessStep.treatSessStep(SnpSessStep.java)
     at com.sunopsis.dwg.dbobj.SnpSession.treatSession(SnpSession.java)
     at com.sunopsis.dwg.cmd.DwgCommandSession.treatCommand(DwgCommandSession.java)
     at com.sunopsis.dwg.cmd.DwgCommandBase.execute(DwgCommandBase.java)
     at com.sunopsis.dwg.cmd.e.i(e.java)
     at com.sunopsis.dwg.cmd.g.y(g.java)
     at com.sunopsis.dwg.cmd.e.run(e.java)
     at java.lang.Thread.run(Unknown Source)
Pls tell me where i am going wrong?

Answer 1

SaraHrry wrote:
Is it a best practice to open a connection to database in a Constructor in Java ???No. A constructor should simply put a newly created object into a valid usable state. Unless that class' responsibility is simply to be some sort of proxy for a connection, or perhaps a connection pool, establishing the connection would not be part of that initial state, and maybe not even in those cases.