Bug 59326 DeferredMethodWrapper needs to update imports
We are going to move IElementCollector to org.eclipse.ui.progress in M9 so please update your imports accordingly in DeferredMethodWrapper . The org.eclipse.ui.progress.IElementCollector currently extends org.eclipse.jface.progress.IElementCollector but this dependency will be severed in M9 and the jface version will be deleted.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/callhierarchy/DeferredMethodWrapper.java
fProvider.startFetching();
            DeferredMethodWrapper methodWrapper = (DeferredMethodWrapper) object;
            collector.add((Object[]) methodWrapper.getCalls(monitor), monitor);
            collector.done();
        } catch (OperationCanceledException e) {
            collector.add(new Object[] { TreeTermination.SEARCH_CANCELED }, monitor);
        } catch (Exception e) {
            JavaPlugin.log(e);
        } finally {
            fProvider.doneFetching();
        }
    }
    /*
     * (non-Javadoc)
     * 
     * @see org.eclipse.ui.progress.IDeferredWorkbenchAdapter#isContainer()
     */
    public boolean isContainer() {
        return true;
    }
    /*
     * (non-Javadoc)
     * 
     * @see org.eclipse.ui.progress.IDeferredWorkbenchAdapter#getRule()
     */
    public ISchedulingRule getRule(Object o) {
        return new BatchSimilarSchedulingRule("org.eclipse.jdt.ui.callhierarchy.methodwrapper"); 
    }
    /*
     * (non-Javadoc)