Problems comparing two Floats

Question

Hello all,
I keep getting exceptions using the code for a table cell renderer listed below.
Basically, the program blows up whenever the renderer is asked to compare two floats.
Two string values, a string and a float, it does not have the desired effect, but a least it runs.
"     public Object[][] aaTableValues = {
          { new Float( 700.00 ), new Float( 300.00 ), new Float( 400.00 ), "Fred", "Snead", "inform", "detail" },
          { new Float( 1000.00 ), new Float( 200.00 ), new Float( 800.00 ), "Jane", "Smith", "limit", "detail" },
          { new Float( 500.00 ), new Float( 200.00 ), new Float( 300.00 ), "Mary", "Ellis", "inform", "detail" },
          table1.setDefaultRenderer(Object.class, new DefaultTableCellRenderer() {
            public Component getTableCellRendererComponent(JTable table,
                                                    Object value,
                                                    boolean isSelected,
                                                    boolean hasFocus,
                                                    int row,
                                                    int column) {
                super.getTableCellRendererComponent(table, value, isSelected,
                        hasFocus, row, column);
                // Prepare default color        
                Color color = isSelected ? table.getSelectionForeground(): table.getForeground();
                if (column == 1) {
                    float val1 = 0.0F;
                        val1 = ((Float)value).floatValue();
                    float val2 = ((Float)table.getValueAt(row, column - 1)).floatValue();
                    if( val1 > val2) {
                        color = isSelected ? Color.red.brighter() : Color.red;
                setForeground(color);
                return this;
        });I get the runtime exceptions like the following:
"Caught exception updating ExitableJFrame[frame0,0,0,618x430,invalid,layout=java.awt.BorderLayout,resizable,title=AccountActivityTable,defaultCloseOperation=,rootPane=javax.swing.JRootPane[,0,0,618x430,invalid,layout=javax.swing.JRootPane$RootLayout,alignmentX=null,alignmentY=null,border=,flags=2,maximumSize=,minimumSize=,preferredSize=],rootPaneCheckingEnabled=true,EXIT_ON_CLOSE]:
java.lang.NullPointerException
     at FloatRenderer.getTableCellRendererComponent(Compiled Code)
     at javax.swing.JTable.prepareRenderer(JTable.java:2897)
     at javax.swing.plaf.basic.BasicTableUI.paintCell(BasicTableUI.java:968)
     at javax.swing.plaf.basic.BasicTableUI.paintRow(BasicTableUI.java:899)
     at javax.swing.plaf.basic.BasicTableUI.paint(BasicTableUI.java:811)
     at javax.swing.plaf.ComponentUI.update(ComponentUI.java:43)
Does anyone know how to fix this?

Answer 1

If you look again at the error message, you'll see it's a NullPointerException. You are using a null reference. Nothing at all to do with comparing two float values. I'd guess that "table.getValueAt(row, column - 1)" is returning null, but it's hard to tell without a line number. You need to do some debugging in that code to see where you are using the null reference.