NetBeans Developer FAQ

This is the developer-oriented FAQ for NetBeans IDE 4.x, 5.x, and 6.x. Developer in this context means "person writing NetBeans extension modules (plug-ins), or applications based on the NetBeans platform". Don't see your developer-oriented question here? Ask on dev@openide.netbeans.org (subscribe to post). Not writing modules? See the list of other FAQs.

For offline use, you can also download the entire FAQ as a giant HTML file. (Automatically refreshed daily.)

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Getting Started

• Becoming a proficient module developer
• How do I get sources for NetBeans using Mercurial (hg)?
• What API do I want to use for x, y or z?
• I have fixed a bug in NetBeans. Can I contribute the patch?
• I have written a module for NetBeans. Can I contribute it to the NetBeans project?
• I have written a module. Can I sell it?
• Why are some packages org.netbeans.api.something and others are org.netbeans.something.api?
• What is netbeans.exe, who compiles it and why is it there?
• How do I get commit access to NetBeans source repository?
• Where can I find Javadoc for the IDE and Platform?
• Where is the Platform and how can I build it?

Tutorials and important starting points

• What are the basic things I should know about NetBeans' architecture to get started?
• Any tutorials out there, please?
• NetBeans API starting point
• Quick Start Guide for NetBeans Plug-in Modules
• Translating your NetBeans module

Getting support, where to find examples

• NetBeans mailing lists - get help from experts all around the globe
• Search the support list for module developers
• Search the NetBeans development mailing list
• Filing a bug report
• Examples of how to use various APIs
• Browse Samples Online
• Consider all of these support options

Development issues, module basics and classpath issues, and information about RCP/Platform application configuration

• My module uses some libraries. I've tried setting CLASSPATH but it doesn't work. Help!
• How do module dependencies/classloading work?
• How do I have two source directories within one module?
• What classloaders are created by the module system?
• Why can't I load properties using UIDefaults?
• I need to package some third party libraries with my module. How do I do that?
• What is an "NBM"?
• Can I sign NBMs I create?
• My module requires JDK 5.0, or 6.0 - how do I keep it from being loaded on an older release?
• What is a library wrapper module and how do I use it
• When should I use a library wrapper module and when should I just package the library into my module?
• How to store external libraries in the NetBeans CVS repository
• What is an implementation dependency and what/how/when should I use one?
• My module uses class XYZ from NetBeans' APIs. It compiles, but I get a NoClassDefFoundError at runtime. What gives?
• Help! What is my class path? Why am I getting NoClassDefFoundErrors?
• What is a module cluster?
• What is the difference between a suite and a cluster?
• Whenever I start NetBeans, I get warnings that some modules use deprecated APIs. Is that why XYZ doesn't work?
• My project.xml lists more dependencies than I really need. How can I fix it?

• Is there a standard way to provide user documentation (help) for my module?
• Where is TopManager? I'm trying to do the examples from the O'Reilly book
• There is a class under org.netbeans.core that does what I need. Can I depend on it?
• Common calls that should be done slightly differently in NetBeans than standard Swing apps (loading images, localized strings, showing dialogs)
• How do I create a patch for a preexisting NetBeans module?
• I want to combine the 5.0 Platform with the 5.0 Update 1 build harness in one binary. Can I?
• I am developing a NetBeans module. What performance criteria should it satisfy?
• I want to set some flags or CLI arguments for running my NB RCP/Platform based application (such as disable assertions). How do I do that?
• How can I fix memory leaks?
• How can I profile NetBeans?

Configuration: How modules install things

• What are the ways a module can influence the system?
• When do I use what registration method?
• Installing things declaratively vs. installing things programmatically
• What is the "default Lookup"?
• How do I run some code when my module starts/loads/unloads?
• What is a module layer (XML layer) or layer file
• What is the system filesystem
• How can I see the filesystem?
• What are .instance files
• What are .settings files
• What are .shadow files
• What is the user dir, what is in it, and why do I need one?
• How do I specify the order for my menu items/toolbar buttons/files in the system filesystem?
• I want to disable a module programmatically. How?

Actions: How to add things to Files, Folders, Menus, Toolbars and more

• How do I add an action to the main menu?
• How do I add an action to a toolbar in the main window?
• How do I make an action that is automatically enabled/disabled depending on what's selected?
• What is the Actions folder in the system filesystem, and why should I use it?
• How do I add an action to all files of a given mime-type?
• How do I add an action to the text-editor popup menu?
• How do I add an action to a project popup menu?
• How do I add an action to a project popup menu of a specific project type?
• How do I add an action to a project popup menu of my own project type?
• How do I add an action to a folder?
• How do I add an action to my custom node?
• How do I make my Node have a submenu on its popup menu?
• How do I can I add an action to the Tools menu for every node?
• How do I add a dropdown menu to toolbar?
• How do I hide/show toolbar dynamically?
• Some module in the IDE etc. already has a menu item I like, but I just want to rename it. Can I?
• Can I change the contents of a menu according to the selected file in the editor, or hide or show a whole menu?
• Can I install submenus into popups or other menus, instead of a regular action?
• How do i change the closing action of the MainWindow?
• How do I get the Open File item on the File menu into my platform application?
• Looking at the UI how do I find a module that implements a menu item
• How can I add a JSeparator to the main toolbar?

Key Bindings

• How do key bindings work?
• Binding one key to more than one action
• Why should I use D- for Ctrl and O- for Alt? I thought C- stood for Ctrl and A- stood for Alt!
• I want my action to appear between to existing items/in a specific place in the menu. Can I do that?
• Why do ordering attributes need boolvalue="true"?
• What about editor-specific keybindings?

Lookup

• What is a Lookup?
• What uses Lookup?
• Why use Lookup - wouldn't a Map be good enough?
• How do I get started using Lookup?
• How do I use Java generics with Lookup?
• What is the "default Lookup"?
• How can I override an instance in the Lookup?
• What is the difference between getCookie(Class), SharedClassObject.findObject(Class) and Lookup.lookup(Class)?
• How do I implement my own lookup or proxy another one?
• If there is more than one of a type in a Lookup, which instance will I get?
• How can I find out what is in a Lookup
• How can I add support for lookups on nodes representing my file type?
• After adding my class to Lookup I get a "ClassNotFoundException" when trying to look it up, why?
• Event Bus in NetBeans

Files and Data Objects

• How does NetBeans recognize files?
• What is a FileObject?
• What is a FileSystem?
• What are file attributes?
• What is a DataObject?
• What is a DataLoader?
• How can I be notified when a file is modified and saved?
• How do I add a menu item to the popup menu of every folder in the system?
• Can I add a menu item to the context menu of every Java source file?
• I'm having trouble implementing this filesystem....
• How do I add support for an XML type with a different extension?
• The next button is never enabled when I create my DataObject from a template. Help!
• How can I create a FileObject in memory?

Converting between common data types and finding things

• FileObjects versus Files
• URIs and URLs
• How do I get a java.io.File for a FileObject?
• How do I get a FileObject for a File?
• How do I get a DataObject for a FileObject?
• How do I get a FileObject for a DataObject?
• How do I get a Node for a DataObject?
• How do I get a DataObject for a Node?
• How do I get a reference to the system filesystem?
• I have a .instance file. How do I get an actual object instance?
• I have a folder full of .instance files. How do I get any/all of the object instances?

Editor and Edited Files

• How can I open a file in the editor in read-only mode?
• Is it safe to programmatically modify a file which is open in the editor?
• How can I get a list of open editor windows?
• How can I get the position of the caret in the currently selected editor window?
• How can I open a particular file at a particular line number?
• Can I add a menu item to the context menu of the Java source editor?
• How can I find the currently open document in the selected editor?
• How can I track what file the user is currently editing?
• I want to make some programmatic changes to the edited file. How can I do it so one Undo undoes it all?
• Can I add syntax coloring for my own data object/MIME type?
• What is MimePath?
• What is MimeLookup?
• How is MimeLookup composed?
• How can I create JEditorPane for a specific document type?
• How to get mime type from Document or JTextComponent?
• How to add code completion to any JEditorPane
• Project Encoding vs. File Encoding - What are the precedence rules used in NetBeans 6.0?

Module System

• I want my module to disable some of the modules that would normally be enabled. Possible?
• I want to disable a module programmatically. How?
• How do I debug a module I'm building?
• Can I control the Auto Update without showing its UI?
• Can I disable Auto Update (for example, while running tests)?
• How can I change the NetBeans splash screen shown when an installed module requires restart?
• How can I obfuscate a module?
• Why am I getting a ClassCastException when the class is clearly of the right type?
• Can two or more modules contain the same package?

Nodes and Explorer

• What is a Node?
• What is "explorer"?
• What is an ExplorerManager?
• What is an Explorer View?
• How do I show a Node in my explorer view?
• I need to create my own Nodes. What should I subclass?
• I need to show Nodes for objects that are slow to create. How do I compute Node children on a background thread?
• How do I create a TopComponent (tab in the main window) to show some Nodes?
• I have a reference to an existing Node from some other module. Can I add cookies/properties/children?
• Can I add or remove children of a node on the fly?
• How do I make a particular node visible in the Explorer, and maybe select it?
• How do I get at the file that a particular node represents?
• Tracking selections in the Explorer
• I need to customize the content of my Node's Lookup. How do I do it?
• I need to write some code that tracks the global selection. What should I do?
• How do I "decorate" nodes that come from another module (i.e. add icons, actions)?
• How do I preserve the column attributes of a TreeTableView?
• How do I remove the "..." buttons of a TreeTableView?
• How can I make sortable columns in a TreeTableView?
• How can I add a "View" capability for data my node represents?
• How can I implement "Select all/Deselect all/Invert selection" features?
• Why do my nodes in the Explorer always have an expand-box by them, even though they have no children?
• How can I prevent (or override) the node deletion dialog?
• How can I change my node's appearance?

Command Line Parsing

• Can something that the user sets on the command line determine whether a menu item is enabled?
• Same as the above, but this time for enabling/disabling modules?
• How to pass command line arguments to a Netbeans Platform application when run inside the IDE

Settings

• How do I let the user set preferences/options/customization/configuration for my module/application?
• Can I add new panels to the Options window?

• I added a SystemOption via layer, but changes at runtime are not persisted. What's going on?
• What's the difference between a .settings file and a SystemOption?
• Is there a simple example of how to use SystemOption?

Window System

• What is the window system
• What are Modes?
• What are TopComponents?
• How do I use Matisse/GroupLayout (new form editor/layout manager in 5.0) in my windowing system components
• I want to show my own component(s) in the main window - where do I start?
• Windows and dialogs
• How does the XML API for installing window system components work?
• How do I use .wstcrf/.wsmode/.settings files to install my module's components in the window system?
• My TopComponent always opens in the editor area, but I want it to open in the same place as XYZ
• Why does TopComponent have a getLookup() method? What is it for?
• I want to disable the popup menu on the toolbars in the main window. How do I do that?
• How can I change the executable's icon?
• How does the window system ''really'' work?

Dialogs API

• How can I control when the OK button is enabled

XML Multiview API

• How do I get started with the XML Multiview API? Part 1, Part 2, Part 3, Part 4, Part 5, Part 6, Part 7

Project Types

• Is it possible to extend an existing project type?
• How do I add an action to a project popup menu?
• How do I add an action to a project popup menu of a specific project type?
• How do I identify the "main project"?

Saving

• Help, the Save menu item is disabled!
• Hmmm. Is there a better solution?
• I have a Save menu item, but no Save button in the toolbar!

Printing

• Help, the Print menu item is disabled!
• Okay, so the Print menu item is enabled. Now, what next?

Wizards and Templates

• How do I make a file template which actually creates a set of files at once?
• I am creating a non-IDE application. How do I enable/control templates?
• How do I get started using FreeMarker to generate my templates? (and this plugin might help too)
• How do I show that a user has filled an invalid input into my wizard?

Properties and PropertySheet

• How do I change the default behavior of PropertySheet editors?
• How do I show my node's properties in the Properties view?
• How do I display different groups of properties on buttons in the property sheet the way Matisse does?
• How do I color the cells in a property sheet?
• How do I display an icon in my property sheet?

Output Window

• How do I create my own tab in the output window and write to it?
• How do I route the output from an external process to the output window?

Annotations

• I want to add annotations to my editor, for errors, or other reasons. How?

Using Enterprise Resources from NetBeans module

• Java EE Application Client on top of NetBeans Platform Tutorial
• How to call EJB from NetBeans module

Writing tests

• Testing things that use FileObjects
• Writing Tests for DataObjects and DataLoaders
• How Do I Set Up Automated Builds and Testing For My Platform Application?
• How do I write GUI tests for NetBeans Platform apps?
• Do you have an example of a GUI test for NetBeans Platform apps?

Branding your application

• Branding About Dialog
• Branding Updater Splash
• How do I set the version number?

Login Screen

• Building a Login Screen for a NetBeans Platform Application (Part 1)
• Building a Login Screen for a NetBeans Platform Application (Part 2)
• Building a Login Screen for a NetBeans Platform Application (Part 3)

Logging

• Using java.util.logging in NetBeans
• UI Logging through Gestures Collector

Tip of the Day

• Tip of the Day Functionality for a NetBeans Platform Application

JavaHelp

• How do I change the default help topic?
• How do I change "IDE Help" in the title bar?
• How do I remove the helpset?
• How do I connect ui to JavaHelp?

Native libraries in NetBeans

• How do I add native libraries?

Custom Project Types

• How do I create a Custom Project Type?
• Why don't previously opened editors return when I re-open my project?

Look and Design

• DevFaqChangeLookAndFeel
• I have a custom component. How can I make it respond to --fontsize like the rest of NetBeans

Deploying Changes through AutoUpdate

• How can I use AutoUpdate to deploy updates and new modules for my application?
• How can I update the splash screen, title bar and other branding items via AutoUpdate?

Programmatic access to Java Sources

The following applies only to NetBeans 6.0 and 6.1. See Java_DevelopersGuide for details.

• How do I Get All Methods/Fields/Constructors of a Class?
• How do I do modification to a source file?

Some more questions that could be answered

Create a new file and set its contents to something?

I added a bunch of cookies to my data object, but still things like Open are not on the context menu.

Listen to renames, deletes, creations, modifies, saves of files?

What is a "data object representation class" anyway?

How to capture double-click on a node to do something else? What about when a template is instantiated?

How do I tell when a piece of source code has been modified by the user?

Can I add templates from my module? What is the easiest way to do this?

What is the relationship between EditorCookie, StyledDocument, and NbDocument & EditorSupport?

Save, rename a file?

How can i show and hide menu items depending on condition?

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