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PONullPointerException error
 

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  1. PONullPointerException error
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    <p>I have a created a class that inherits from the Manager class that will act as a holder for <strong>four</strong> other abstract classes called AbstractColumn.</p> <p>Imagine a table with 4 columns, the table itself is the main class, and each column is AbstractColumn.</p> <p>I don't understand why I would get this error.</p> <p>Here are my classes.</p> <p><strong>The Main ColumnHolder.java class</strong></p> <pre><code>package tec.expenses; import net.rim.device.api.system.Bitmap; import net.rim.device.api.ui.Manager; import net.rim.device.api.ui.component.BitmapField; import net.rim.device.api.ui.component.LabelField; import net.rim.device.api.ui.container.VerticalFieldManager; import net.rim.device.api.ui.decor.Background; import net.rim.device.api.ui.decor.BackgroundFactory; public class ColumnHolderManager extends Manager{ private AbstractColumn Entry; private AbstractColumn Category; private AbstractColumn Date; private AbstractColumn Amount; protected ColumnHolderManager(long style){ super(style); Background mainBackground = BackgroundFactory.createSolidBackground(0xEEEEEE); setBackground(mainBackground); AbstractColumn Entry = new AbstractColumn("Entry", NO_HORIZONTAL_SCROLL); AbstractColumn Category = new AbstractColumn("Category", NO_HORIZONTAL_SCROLL); AbstractColumn Date = new AbstractColumn("Date", NO_HORIZONTAL_SCROLL); AbstractColumn Amount = new AbstractColumn("Amount", NO_HORIZONTAL_SCROLL); add(Entry); add(Category); add(Date); add(Amount); } protected void sublayout(int width, int height) { /*layoutChild(this.Entry, 85, 50); setPositionChild(this.Entry, 10, 10 ); layoutChild(this.Category, 85, 50); setPositionChild(this.Category, 40, 0 ); layoutChild(this.Date, 85, 50); setPositionChild(this.Date, 70, 0 ); layoutChild(this.Amount, 85, 50); setPositionChild(this.Amount, 100, 0 );*/ setExtent(360, 203); } } </code></pre> <p><strong>The abstract AbstractColumn class</strong></p> <pre><code>package tec.expenses; import net.rim.device.api.system.Bitmap; import net.rim.device.api.ui.Manager; import net.rim.device.api.ui.component.BitmapField; import net.rim.device.api.ui.component.LabelField; import net.rim.device.api.ui.decor.Background; import net.rim.device.api.ui.decor.BackgroundFactory; public class AbstractColumn extends Manager { LabelField labelHeader; protected AbstractColumn(String header, long style){ super(style); Background mainBackground = BackgroundFactory.createSolidBackground(0xCACACA); setBackground(mainBackground); this.labelHeader = new LabelField(header); add(labelHeader); } protected void sublayout(int width, int height) { layoutChild(labelHeader, 80, 30); setPositionChild(labelHeader, 5, 5); setExtent(90, 50); } } </code></pre> <p>As you can see the classes are very simple yet I cannot understand why I would get this error. </p> <p>I'm making this application for Blackberry using Eclipse as the IDE.</p> <p>When I comment out the Sublayout methods' setPositionChild methods I no longer get the exception which means that in the constructor of the ColumnHolderManager class, creating the new AbstractColumn objects aren't really getting created.</p> <p>Any help?</p>
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    1. PO
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      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USMichael Donohue
    1. This table or related slice is empty.
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    1. This table or related slice is empty.
    1. This table or related slice is empty.
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    2. PO
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    1. VO
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      1. PONullPointerException error
      1. This table or related slice is empty.
      1. VTDownMod
    2. VO
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      1. PONullPointerException error
      1. This table or related slice is empty.
      1. VTUpMod
    1. COtoo many code to be called "very SIMPLE"...sorry
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      1. USTopera
    2. COCould you provide a stack trace?
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      1. USsoftcr
    3. COI cannot provide a stack trace because I don't know how to run Eclipse well enough sorry.
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      1. This table or related slice is empty.
 

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