java - variable in web service operation not being updated -

i creating simple web service example java. have variable num initialized 0, not able retain value @ end. value should incremented 1 per db have.

here web service operation:

@webmethod(operationname = "getnewid") public string getnewid(@webparam(name = "newid") string txt2)  { connection connection = null;   resultset resultset = null;   statement statement = null; int num=0;     try          {               class.forname("org.sqlite.jdbc");               connection = drivermanager.getconnection("jdbc:sqlite:src/java/db/test.sqlite");               statement = connection.createstatement();             resultset = statement.executequery("select id logindetails id = '"+txt2+"'");              while (resultset.next())                  {                       //system.out.println("your id "+ resultset.getstring("id"));                     num++;                 }          }       catch (exception e)          {               system.out.println("you had exception");             e.printstacktrace();           }               {           try              {                   resultset.close();                   statement.close();                   connection.close();               }          catch (exception e)              {                   e.printstacktrace();               }           }      if(num==0)         {              return "your id not match";         }      else         {             return "welcome "+txt2;         } } 

in output getting

method returned java.lang.string : "your id not match"

for cases if part working , not else. when tried same method inside class working fine, not in case of web service operation

new code

@webmethod(operationname = "getnewid") public string getnewid(@webparam(name = "newid") string txt2)  { string str = null; connection connection = null;   resultset resultset = null;   statement statement = null;     int num=0;     try          {               class.forname("org.sqlite.jdbc");               connection = drivermanager.getconnection("jdbc:sqlite:src/java/db/test.sqlite");               statement = connection.createstatement();             resultset = statement.executequery("select id logindetails id = '"+txt2+"'");              while (resultset.next())                  {                       //system.out.println("your id "+ resultset.getstring("id"));                     num++;                 }          }       catch (exception e)          {               system.out.println("you had exception");             e.printstacktrace();           }               {           try              {                   resultset.close();                   statement.close();                   connection.close();               }          catch (exception e)              {                   e.printstacktrace();               }           }      assert num == 0 || txt2 == null : str = "num "+num+"txt2 "+txt2;     return str;      /*if(num==0)         {              return "your id not match please try again or if new user please register";         }      else         {             return "welcome "+txt2;         }*/ } 

in result getting value of str null.

ok tried ..

@webmethod(operationname = "getnewid")  public string getnewid(@webparam(name = "newid") string txt2)  { connection connection = null;   resultset resultset = null;   statement statement = null; int num=0;     try          {               class.forname("org.sqlite.jdbc");               connection = drivermanager.getconnection("jdbc:sqlite:src/java/db/test.sqlite");               statement = connection.createstatement();             resultset = statement.executequery("select id logindetails id = '"+txt2+"'");              while (resultset.next())                  {                       num++;                 }             return resultset.tostring();          }       catch (exception e)          {               system.out.println("you had exception");             e.printstacktrace();             return "you had exception";         }   } 

i getting output

java.lang.string : "you had exception" 

when working fine outside web service operation why showing exception here... , how can correct ?

1. check exceptions
2. debug code via debugger, assert statements or if need system.out.println statements.
3. if able, run query against db first , see if expected result.
4. make sure class driver being loaded loads properly. make sure lib in class path.

regards rentius