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POSimpleDoubleProperty.set(double) throwing NPE
 

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  1. POSimpleDoubleProperty.set(double) throwing NPE
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    <p>I have a small financial application that is showing a market data watch list (current bid price/current ask price) in a TableView.</p> <p>The bid/ask prices are being updated in real time for each of the symbols that I'm watching.</p> <p>Everything works exceptionally well, but occasionally I get a NullPointerException when trying to set either the bid or sometimes the ask price.</p> <p>Here's a snippet from my GUI Controller that sets up the TableView and Columns</p> <pre><code>TableColumn&lt;PositionRowData, Number&gt; bidColumn = new TableColumn&lt;PositionRowData, Number&gt;(BID_COLUMN_NAME); TableColumn&lt;PositionRowData, Number&gt; askColumn = new TableColumn&lt;PositionRowData, Number&gt;(ASK_COLUMN_NAME); TableColumn&lt;PositionRowData, Number&gt; lastColumn = new TableColumn&lt;PositionRowData,Number&gt;(LAST_COLUMN_NAME); . . . //and later on the column is initialized like this bidColumn.setCellFactory(new USDTableCellRenderer()); bidColumn.setCellValueFactory(new Callback&lt;TableColumn.CellDataFeatures&lt;PositionRowData,Number&gt;, ObservableValue&lt;Number&gt;&gt;() { @Override public ObservableValue&lt;Number&gt; call( CellDataFeatures&lt;PositionRowData, Number&gt; arg0) { return arg0.getValue().getBid(); } }); //finally the columns are added to the table TableView.getColumns().addAll(....bidColumn..etc); </code></pre> <p>Here's a snippet from my PositionRowData constructor with initialization:</p> <pre><code>bid = new SimpleDoubleProperty(); ask = new SimpleDoubleProperty(); </code></pre> <p>Here's what my setter code looks like: </p> <pre><code>public void setBid(double bid) { try { this.bid.set(bid); } catch (NullPointerException e) { _log.error("Would have been NPE in setBid. trying to set new value: "+bid); } } </code></pre> <ul> <li>Btw - It's not my usual habit to catch my NPEs! I just stuck that in there because I wanted a more graceful error for the person who was testing this for me!</li> </ul> <p>Here's the full stack trace:</p> <pre><code>2013-06-20 11:56:12,500 ERROR [DataChannel Reader Thread] - NPE java.lang.NullPointerException at com.sun.javafx.binding.ExpressionHelper$Generic.fireValueChangedEvent(Unknown Source) at com.sun.javafx.binding.ExpressionHelper.fireValueChangedEvent(Unknown Source) at javafx.beans.property.DoublePropertyBase.fireValueChangedEvent(Unknown Source) at javafx.beans.property.DoublePropertyBase.markInvalid(Unknown Source) at javafx.beans.property.DoublePropertyBase.set(Unknown Source) at com.eak070.ui.tablemodel.PositionRowData.setAsk(PositionRowData.java:86) at com.eak070.ui.ETGUIController.onQuote(ETGUIController.java:808) at com.eak070.ui.ETGUIController$24.handleDataChannelMessage(ETGUIController.java:737) at com.eak070.communication.stream.DataChannel.processDataChannelMessage(DataChannel.java:211) at com.eak070.communication.stream.DataChannel.readFromSocketChannel(DataChannel.java:156) at com.eak070.communication.stream.DataChannel.access$1(DataChannel.java:122) at com.eak070.communication.stream.DataChannel$1.run(DataChannel.java:99) </code></pre> <p>I'm not quite sure what's going on as I'm still somewhat new to JavaFX and don't really know the ins and outs of bindings.</p> <p>This appears to be happening sporadically. In other words I can't yet reproduce it on purpose. It just happens seemingly randomly.</p> <p>This feels like it might be a threading issue, but I'm just not sure why there's a NPE inside of the set() method since rows in this table aren't being destroyed. Once rows are created they hang around forever. Any advice/thoughts appreciated.</p>
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    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PTQuestion
    1. USeak12913
    1. USeak12913
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    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
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      1. PTAnswer
    2. PO
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      1. PTAnswer
    1. This table or related slice is empty.
    1. COIs this setter running in the GUI event thread or another thread?
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      1. POSimpleDoubleProperty.set(double) throwing NPE
      1. USPeter Lawrey
    2. COPlease show us the stack trace
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      1. POSimpleDoubleProperty.set(double) throwing NPE
      1. USDaniel Kaplan
    3. CO@PeterLawrey - the setter is running in another thread.
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      1. POSimpleDoubleProperty.set(double) throwing NPE
      1. USeak12913
 

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