NMS Reflection: This gist is an example of using reflection to use net.minecraft.server classes to set a block, without the need to import the net.minecraft.server.X.* packages, where X is the current Bukkit version/revision (i.e. v1_6_R2). This way, there will be no need to recompile plugins every time Bukkit releases a new revision.

Main.java

package com.daviga404.NMSReflection;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.bukkit.block.Block;
import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.block.Action;
import org.bukkit.event.player.PlayerInteractEvent;
import org.bukkit.plugin.java.JavaPlugin;

public class Main extends JavaPlugin implements Listener {
	
	// The original classes in reflected variable form, named as they would normally be.
	private Class<?> CraftWorld, World;
	
	// The methods in the classes (CraftWorld#getHandle, World#setTypeIdAndData)
	private Method getHandle, setTypeIdAndData;
	
	public void onEnable() {
		
		try {
			// Setup the reflection as the plugin enables, this will save time later.
			setupReflection();
			getServer().getPluginManager().registerEvents(this, this);
		} catch (NoSuchMethodException | SecurityException e) {
			e.printStackTrace();
		}
		
	}
	
	@EventHandler
	public void onPlayerInteract(PlayerInteractEvent e) {
		
		if (e.getAction().equals(Action.RIGHT_CLICK_BLOCK)) {
			Block b = e.getClickedBlock();
			int typeId = 89;
			int data = 0;
			
			try {
				// Simply pass the Bukkit Block, a type ID and data to the method.
				setBlockNatively(b, typeId, data);
			} catch (IllegalAccessException | IllegalArgumentException | InvocationTargetException e1) {
				e1.printStackTrace();
			}
		}
		
	}
	
	// Stores the reflected classes & methods in variable for access later
	private void setupReflection() throws NoSuchMethodException, SecurityException {
		
		CraftWorld = getNMSClass("org.bukkit.craftbukkit.%s.CraftWorld");
		World = getNMSClass("net.minecraft.server.%s.World"); 
		getHandle = CraftWorld.getDeclaredMethod("getHandle", new Class<?>[]{});
		setTypeIdAndData = World.getDeclaredMethod("setTypeIdAndData", int.class, int.class, int.class, int.class, int.class, int.class);
		
	}
	
	// Mimics the original World#setTypeIdAndData method in the NMS class.
	private void setBlockNatively(org.bukkit.block.Block b, int typeId, int data) throws IllegalAccessException, IllegalArgumentException, InvocationTargetException {
		
		Object craftWorld = getHandle.invoke(CraftWorld.cast(b.getWorld()), new Object[]{});
		setTypeIdAndData.invoke(craftWorld, b.getX(), b.getY(), b.getZ(), typeId, data, 0);
		
	}

	/* Uses regex and reflection to find all packages which contain the NMS version,
	   then retrieves the class from the argument by the fully qualified name. */
	private Class<?> getNMSClass(String nmsClass) {
		
		String version = null;
		Pattern pat = Pattern.compile("net\\.minecraft\\.(?:server)?\\.(v(?:\\d_)+R\\d)");
		for (Package p : Package.getPackages()) {
			String name = p.getName();
			Matcher m = pat.matcher(name);
			if (m.matches()) version = m.group(1);
		}
		
		if (version == null) return null;
		
		try { 
			return Class.forName(String.format(nmsClass, version));
		} catch (ClassNotFoundException e) {
			return null;
		}
		
	}
	
}