package edu.cuny.citytech.defaultrefactoring.ui.handlers;

import java.util.List;
import java.util.Optional;

import org.eclipse.core.commands.AbstractHandler;
import org.eclipse.core.commands.ExecutionEvent;
import org.eclipse.core.commands.ExecutionException;
import org.eclipse.core.runtime.Status;
import org.eclipse.core.runtime.jobs.Job;
import org.eclipse.jdt.core.IMethod;
import org.eclipse.jdt.core.JavaModelException;
import org.eclipse.jdt.internal.ui.JavaPlugin;
import org.eclipse.jdt.internal.ui.util.SelectionUtil;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.ui.handlers.HandlerUtil;

import edu.cuny.citytech.defaultrefactoring.ui.plugins.MigrateSkeletalImplementationToInterfaceRefactoringPlugin;
import edu.cuny.citytech.defaultrefactoring.ui.wizards.MigrateSkeletalImplementationToInterfaceRefactoringWizard;

/**
 * Our sample handler extends AbstractHandler, an IHandler base class.
 * 
 * @see org.eclipse.core.commands.IHandler
 * @see org.eclipse.core.commands.AbstractHandler
 */
public class MigrateSkeletalImplementationToInterfaceHandler extends AbstractHandler {

	/**
	 * the command has been executed, so extract extract the needed information
	 * from the application context.
	 */
	@Override
	public Object execute(ExecutionEvent event) throws ExecutionException {
		ISelection currentSelection = HandlerUtil.getCurrentSelectionChecked(event);

		List<?> list = SelectionUtil.toList(currentSelection);
		IMethod[] methods = list.stream().filter(e -> e instanceof IMethod).toArray(length -> new IMethod[length]);

		if (methods.length > 0) {
			Shell shell = HandlerUtil.getActiveShellChecked(event);
			HandlerUtil.getActiveWorkbenchWindowChecked(event).getWorkbench().getProgressService().showInDialog(shell,
					Job.create("Migrate skeletal implementation to interface", monitor -> {
						try {
							MigrateSkeletalImplementationToInterfaceRefactoringWizard.startRefactoring(methods, shell,
									Optional.of(monitor));
							return Status.OK_STATUS;
						} catch (JavaModelException e) {
							JavaPlugin.log(e);
							return new Status(Status.ERROR, MigrateSkeletalImplementationToInterfaceRefactoringPlugin
									.getDefault().getBundle().getSymbolicName(), "Failed to start refactoring.");
						}
					}));
		}

		return null;
	}
}

package edu.cuny.citytech.defaultrefactoring.ui.handlers;

import java.util.List;
import java.util.Optional;

import org.eclipse.core.commands.AbstractHandler;
import org.eclipse.core.commands.ExecutionEvent;
import org.eclipse.core.commands.ExecutionException;
import org.eclipse.core.runtime.Status;
import org.eclipse.core.runtime.jobs.Job;
import org.eclipse.jdt.core.IMethod;
import org.eclipse.jdt.core.JavaModelException;
import org.eclipse.jdt.internal.ui.JavaPlugin;
import org.eclipse.jdt.internal.ui.util.SelectionUtil;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.ui.handlers.HandlerUtil;

import edu.cuny.citytech.defaultrefactoring.ui.plugins.MigrateSkeletalImplementationToInterfaceRefactoringPlugin;
import edu.cuny.citytech.defaultrefactoring.ui.wizards.MigrateSkeletalImplementationToInterfaceRefactoringWizard;

public class MigrateSkeletalImplementationToInterfaceHandler extends AbstractHandler {

	/**
	 * the command has been executed, so extract extract the needed information
	 * from the application context.
	 */
	@Override
	public Object execute(ExecutionEvent event) throws ExecutionException {
		ISelection currentSelection = HandlerUtil.getCurrentSelectionChecked(event);

		List<?> list = SelectionUtil.toList(currentSelection);
		IMethod[] methods = list.stream().filter(e -> e instanceof IMethod).toArray(length -> new IMethod[length]);

		if (methods.length > 0) {
			Shell shell = HandlerUtil.getActiveShellChecked(event);
			HandlerUtil.getActiveWorkbenchWindowChecked(event).getWorkbench().getProgressService().showInDialog(shell,
					Job.create("Migrate skeletal implementation to interface", monitor -> {
						try {
							MigrateSkeletalImplementationToInterfaceRefactoringWizard.startRefactoring(methods, shell,
									Optional.of(monitor));
							return Status.OK_STATUS;
						} catch (JavaModelException e) {
							JavaPlugin.log(e);
							return new Status(Status.ERROR, MigrateSkeletalImplementationToInterfaceRefactoringPlugin
									.getDefault().getBundle().getSymbolicName(), "Failed to start refactoring.");
						}
					}));
		}

		return null;
	}
}

Remove nonsensical comment.