Bug 134750 [DataBinding] TextObservableValue throws NPE on change if the intial model value is null
When binding a Text to a model attribute that has an intial value of null ObservableTextValue throws a NPE when updating the view. In "updateListener" it assumes that oldValue != null. I'll attach a JUnit that throws the Exception.
bundles/org.eclipse.jface.databinding/src/org/eclipse/jface/internal/databinding/internal/swt/TextObservableValue.java
}
		};
		text.addKeyListener(keyListener);
	}
	public void doSetValue(final Object value) {
		try {
			updating = true;
			bufferedValue = (String) value;
			text.setText(value == null ? "" : value.toString()); 
		} finally {
			updating = false;
		}
	}
	public Object doGetValue() {
		return text.getText();
	}
	public Object getValueType() {
		return String.class;
	}
	public void dispose() {
		if (!text.isDisposed()) {
			if (updatePolicy != SWT.None) {
				text.removeListener(updatePolicy, updateListener);
			}
			text.removeVerifyListener(verifyListener);
		}
		super.dispose();
	}
}