Jtable retruning nulls

[Azoth]

I have this code here:

try{
       for(int i=0;  i<=rows;++i)
    {
       if (Integer.parseInt(StatsTable.getValueAt(i,0).toString()) != 0)
      data[i]=Double.parseDouble(StatsTable.getValueAt(i, 3).toString());
      
      df++;
     
 
     }
       
      }catch(Exception e)   {simplelogger(e);
       JOptionPane.showMessageDialog(null,"Input error: see err.log  for more info.");
      }

It is duplicated in different parts of my program. It gives me the following errors

java.lang.NullPointerException
at MycologyFrame.jPerfromTestButActionPerformed(MycologyFrame.java:9219)
at MycologyFrame.access$20200(MycologyFrame.java:50)
at MycologyFrame$204.actionPerformed(MycologyFrame.java:6718)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2348)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)

Now line 90219 is

 if (Integer.parseInt(StatsTable.getValueAt(i,0).toString()) != 0)

Help

[Norm]

What are the values of the variables on that line? What is the value returned by the getValueAt method?

[Azoth]

I have this code here:

try{
       for(int i=0;  i<=rows;++i)
    {
       if (Integer.parseInt(StatsTable.getValueAt(i,0).toString()) != 0)
      data[i]=Double.parseDouble(StatsTable.getValueAt(i, 3).toString());
      
      df++;
     
 
     }
       
      }catch(Exception e)   {simplelogger(e);
       JOptionPane.showMessageDialog(null,"Input error: see err.log  for more info.");
      }

It is duplicated in different parts of my program. It gives me the following errors

java.lang.NullPointerException
at MycologyFrame.jPerfromTestButActionPerformed(MycologyFrame.java:9219)
at MycologyFrame.access$20200(MycologyFrame.java:50)
at MycologyFrame$204.actionPerformed(MycologyFrame.java:6718)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2348)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)

Now line 90219 is

 if (Integer.parseInt(StatsTable.getValueAt(i,0).toString()) != 0)

Help

It should be
1
2
3
.
.

Like a spreadsheet

[Norm]

It should be

Ok, but what were the actual values?
What variable had the null value?
Add a print statement before the statement (9219) where the NPE happened that prints out the values of the variables and the value returned by the get method so you can see where the null value is.

[Azoth]

The statement (9219) returns
1
2
3

[Norm]

Ok none of those printed values are null.
What variable did those values come from?
What are the values in the other variables used on line 9219?
Print the values in these to see:
StatsTable
StatsTable.getValueAt(i,0)
i

You need to find where the null value is to be able to solve the problem. Printing the values will help you find it.

[Azoth]

The values
1
2
3
came from the the code

if (Integer.parseInt(StatsTable.getValueAt(i,0).toString()) != 0)

When printing out i I get
0
1
2
3
I then changed the loop to

 (for  i=ii<rows;++i)
System.out.print(i);

and got
1
2
3
..
with the same problem arrg

[Norm]

Print the values of these just before line 9219 to see where the null value is:
StatsTable
StatsTable.getValueAt(i,0)
i

What were the values of the above variables just before the NPE happened?
You need to find where the null value is to be able to solve the problem. Printing the values will help you find it.


A cell can contain a null value. Do not call the toString() method with the getValueAt method returns a null value.

[Azoth]

javax.swing.JTable[,0,0,606x160,alignmentX=0.0,alignmentY=0.0,border=javax.swing.border.MatteBorder@129d20b,flags=251658560,maximumSize=,minimumSize=,preferredSize=,autoCreateColumnsFromModel=true,autoResizeMode=AUTO_RESIZE_SUBSEQUENT_COLUMNS,cellSelectionEnabled=false,editingColumn=3,editingRow=3,gridColor=java.awt.Color[r=0,g=0,b=0],preferredViewportSize=java.awt.Dimension[width=450,height=400],rowHeight=16,rowMargin=0,rowSelectionAllowed=true,selectionBackground=DerivedColor(color=57,105,138 parent=nimbusSelectionBackground offsets=0.0,0.0,0.0,0 pColor=57,105,138,selectionForeground=DerivedColor(color=255,255,255 parent=nimbusLightBackground offsets=0.0,0.0,0.0,0 pColor=255,255,255,showHorizontalLines=true,showVerticalLines=true]
javax.swing.JTable[,0,0,606x160,alignmentX=0.0,alignmentY=0.0,border=javax.swing.border.MatteBorder@129d20b,flags=251658560,
Here is printo out of StatsTable

maximumSize=,minimumSize=,preferredSize=,autoCreateColumnsFromModel=true,autoResizeMode=AUTO_RESIZE_SUBSEQUENT_COLUMNS,cellSelectionEnabled=false,editingColumn=3,editingRow=3,gridColor=java.awt.Color[r=0,g=0,b=0],preferredViewportSize=java.awt.Dimension[width=450,height=400],rowHeight=16,rowMargin=0,rowSelectionAllowed=true,selectionBackground=DerivedColor(color=57,105,138 parent=nimbusSelectionBackground offsets=0.0,0.0,0.0,0 pColor=57,105,138,selectionForeground=DerivedColor(color=255,255,255 parent=nimbusLightBackground offsets=0.0,0.0,0.0,0 pColor=255,255,255,showHorizontalLines=true,showVerticalLines=true]
javax.swing.JTable[,0,0,606x160,alignmentX=0.0,alignmentY=0.0,border=javax.swing.border.MatteBorder@129d20b,flags=251658560,maximumSize=,minimum

[Norm]

Is that the value of the varaible: StatsTable?
Ok, that's one of the three, what about the value of this one:
StatsTable.getValueAt(i,0)

[Azoth]

I get
2
3
4
for

 (StatsTable.getValueAt(i,0)

[Norm]

If the NPE happens on this line

if (Integer.parseInt(StatsTable.getValueAt(i,0).toString()) != 0)

and none of the variables have a null value,

I don't understand why you are getting a NPE. There needs to be a null value somewhere.