Thread: Causing NULL POINTER when i add a code;

public DefaultTableModel showTable(DefaultTableModel tmodel, String sql){
        DefaultTableModel tm = tmodel;
        String sq = sql;
 
 
       try {
           st=con.createStatement();
           rs=st.executeQuery(sq);
           System.out.println("Query: "+sq);
 
           ResultSetMetaData rmeta = (ResultSetMetaData)rs.getMetaData();
           int numColumns = rmeta.getColumnCount();
           System.out.println("Column Count: "+numColumns);
 
           for(int i=1;i<=numColumns;i++){
               if(i<=numColumns){
                   System.out.println(rmeta.getColumnName(i));
                   tm.addColumn(rmeta.getColumnName(i));
               } 
           }
 
 
 
       } catch (SQLException ex) {
           Logger.getLogger(JDBCCrud.class.getName()).log(Level.SEVERE, null, ex);
       }
 
 
 
    return tm;
    }//SHOWTABLE

when i add: tm.addColumn(rmeta.getColumnName(i));
the program will show errors which says that it was a NULL POINTER and lead me to this code.

im getting the name of column to the database. and i used this code: System.out.println(rmeta.getColumnName(i)); to check if java gets the data from sqlserver database.

Originally Posted by ZDreamer08

public DefaultTableModel showTable(DefaultTableModel tmodel, String sql){
        DefaultTableModel tm = tmodel;
        String sq = sql;
 
 
       try {
           st=con.createStatement();
           rs=st.executeQuery(sq);
           System.out.println("Query: "+sq);
 
           ResultSetMetaData rmeta = (ResultSetMetaData)rs.getMetaData();
           int numColumns = rmeta.getColumnCount();
           System.out.println("Column Count: "+numColumns);
 
           for(int i=1;i<=numColumns;i++){
               if(i<=numColumns){
                   System.out.println(rmeta.getColumnName(i));
                   tm.addColumn(rmeta.getColumnName(i));
               } 
           }
 
 
 
       } catch (SQLException ex) {
           Logger.getLogger(JDBCCrud.class.getName()).log(Level.SEVERE, null, ex);
       }
 
 
 
    return tm;
    }//SHOWTABLE

when i add: tm.addColumn(rmeta.getColumnName(i));
the program will show errors which says that it was a NULL POINTER and lead me to this code.

im getting the name of column to the database. and i used this code: System.out.println(rmeta.getColumnName(i)); to check if java gets the data from sqlserver database.

is this the same code as this?

no. im disecting my code. so i found the error and it was in the tm.addColumn(rmeta.getColumnName(i));

Originally Posted by ZDreamer08

no. im disecting my code. so i found the error and it was in the tm.addColumn(rmeta.getColumnName(i));

ok have you fixed it? or still need assistance?

still need assistance and as i debug it. i have a bad feeling that it's because of the DefaultTableModel tm; is being the NULL POINTER error. cause when im getting the row information from database, it has the error NULL POINTER too that goes to tm.addRow(data);

Are you sure the table model isn't null when being passed in?

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