Bug 234345 [Viewers] AbstractTreeViewer#getChildren(Widget,Object[]) holds doc that it is experimental
a) Remove the experimental description => Why do we need this method b) Remove the method
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/AbstractTreeViewer.java
int insertionIndexInItems = indexInItems;
				while( insertionIndexInItems < items.length
						&& internalCompare(comparator, parentPath, element,
								items[insertionIndexInItems].getData()) == 0) {
					
					
					
					
					if (items[insertionIndexInItems].getData().equals(element)) {
						
						
						internalRefresh(element);
						
						continue elementloop;
					}
					insertionIndexInItems++;
				}
				
				if (insertionIndexInItems == items.length) {
					createTreeItem(widget, element, -1);
					newItems++;
				} else {
					
					
					
					createTreeItem(widget, element, insertionIndexInItems + newItems);
					newItems++;
				}