ArrayIndexOutOfBoundsException = 0

Question

Got DBTableHeaderFill Error: ArrayIndexOutOfBoundsException = 0

and can't figure it out, why does it appears...

col is 11 because table has 12 headers, as we know the counting starts form 0

i know it looks primitive, but i'm just debugging the problem ... JOptionPane is for seeing what works what not, and i can't figure whats the problem whit arrays...

    Object rows[][] = new Object[row][col];
    Object columns [] = new Object[col];
    row = 1;
    col = 11;
    JTable table = new JTable(rows, columns);
    scrollPane.setViewportView(table);
    /*
     *  DataBase Headers
     */
    try{
        conn = DBConnection.DBConnector();
        JOptionPane.showMessageDialog(null, "Connection");
        Statement st = conn.createStatement();
        JOptionPane.showMessageDialog(null, "Statement");
        rs = st.executeQuery("SELECT * FROM Query1");
        JOptionPane.showMessageDialog(null, "Query1 load");
        ResultSetMetaData rsmd = rs.getMetaData();
        JOptionPane.showMessageDialog(null, rsmd);
        int columnCount = rsmd.getColumnCount();
        JOptionPane.showMessageDialog(null, columnCount);
        JOptionPane.showMessageDialog(null, "test " + col);
        // The column count starts from 0
        for (int i = 1; i < columnCount + 1; i++ ) {
            columns[i-1] = rsmd.getColumnName(i);
            JOptionPane.showMessageDialog(null, "result: " + o);
            JOptionPane.showMessageDialog(null, "Header" + columns[i-1]);
          // Writes headers
        }
    }catch(Exception e){
        JOptionPane.showMessageDialog(null, "DBTableHeaderFill Error: " + e);
    }

When i assign col and row values before arrays i get this errors:

java.lang.NullPointerException at javax.swing.JTable$1.getColumnName(Unknown Source) at javax.swing.JTable.addColumn(Unknown Source) at javax.swing.JTable.createDefaultColumnsFromModel(Unknown Source) at javax.swing.JTable.tableChanged(Unknown Source) at javax.swing.JTable.setModel(Unknown Source) at javax.swing.JTable.(Unknown Source) at javax.swing.JTable.(Unknown Source) at javax.swing.JTable.(Unknown Source) at Main.initialize(Main.java:199) at Main.(Main.java:65) at Main$1.run(Main.java:34) at java.awt.event.InvocationEvent.dispatch(Unknown Source) at java.awt.EventQueue.dispatchEventImpl(Unknown Source) at java.awt.EventQueue.access$300(Unknown Source) at java.awt.EventQueue$3.run(Unknown Source) at java.awt.EventQueue$3.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source) at java.awt.EventQueue.dispatchEvent(Unknown Source) at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source) at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source) at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source) at java.awt.EventDispatchThread.run(Unknown Source)

So i found my problem...

JTable table = new JTable(rows, columns);
scrollPane.setViewportView(table);

this needs to be at the end of the arrays....

i can't avoid it because whit DataBase work i need try{}catche(){} — Mr.Pengu, Feb 16 '15 at 12:46
He means you should catch specific exceptions, not `Exception`. — Hot Licks, Feb 16 '15 at 12:47
yes, but avoid a so general exception ... and a block so big. — Luís Soares, Feb 16 '15 at 12:47
Maybe you should set `row` and `col` before you reference them. — Hot Licks, Feb 16 '15 at 12:50
@ Hot Licks of course it's going be empty, i'm trying to fill the array — Mr.Pengu, Feb 16 '15 at 12:51
@Hot Licks well when i do it it crashes, so... i'm in a dead end.. — Mr.Pengu, Feb 16 '15 at 12:58
Note that your `for` loop, as written, will loop one less time than `columnCount`. — Hot Licks, Feb 16 '15 at 13:21

score 1 · Accepted Answer · answered Feb 16 '15 at 12:51

1

It seems you are initialising your row/col values after using them to create the arrays:

Object rows[][] = new Object[row][col];
Object columns [] = new Object[col];
row = 1;
col = 11;

This should probably be:

row = 1;
col = 11;
Object rows[][] = new Object[row][col];
Object columns [] = new Object[col];

And col should be the exact number of columns your table has, otherwise you are creating an array that's only 11 elements long, instead of 12.

answered Feb 16 '15 at 12:51

tringel

395
1
13

i know, but when i assign the int values before the arrays the whole thing just crashess – Mr.Pengu Feb 16 '15 at 12:54
Then you should find out what causes these crashes. Creating an array with zero values will lead to an array with no elements, hence you can't even address array[0] as is your case. `String[] strings = new String[0]; System.out.println(strings[0]);` Leads to just the **ArrayIndexOutOfBoundsException: 0** that you are experiencing – tringel Feb 16 '15 at 13:02
Thanks, some how forgot about that... got 2 projects going on... and the JTable elements by my look is one of the hardest... – Mr.Pengu Feb 16 '15 at 13:07

score 0 · Answer 2 · answered Feb 16 '15 at 12:49

0

the variable col is set after:

Object columns [] = new Object[col];

What is the value of col, before this line? If it is 0, then that would explain the error you are getting:

Got DBTableHeaderFill Error: ArrayIndexOutOfBoundsException = 0

answered Feb 16 '15 at 12:49

Inactive

16
2

it's 0 but when i assign it before, then the whole thing doesn't work... – Mr.Pengu Feb 16 '15 at 12:52
You have to set it to 11, before using it in Object columns [] = new Object[col]; – Inactive Feb 16 '15 at 12:53

ArrayIndexOutOfBoundsException = 0

2 Answers2