VSNetBeans, the Apache NetBeans Extension for Visual Studio Code, is created as a promotional tool by the Apache NetBeans community for VS Code users.
Install VSNetBeans into VS Code, use it, and maybe you'll want to try the complete Apache NetBeans experience, which is Apache NetBeans. And, if not, that's also fine.
Full Java editing and debugging support is provided by VSNetBeans directly in your VSCode environment. By using VSNetBeans, you're using the same Java tools that are part of Apache NetBeans, so that we hope that VSNetBeans will provide a new avenue for feedback to the Apache NetBeans project.
VS Code already has support for Java, provided by an extension created by Red Hat, though what that extension misses are the following features that VSNetBeans provides out of the box:
- Support for JDK 8. (The Red Hat extension requires JDK 11 or above.)
- Polyglot debugging.
- Support for OpenJDK projects.
Getting Started
Get the latest Apache NetBeans VSCode extension from the official VS Code market place
or download the latest development version of Apache NetBeans Language Server extension and install it into VSCode via Install from VSIX...
Scenarios
Scenario 1: Hello World
1. Get an existing Java project, for example, Micronaut: https://micronaut.io/launch/
Don't forget to select Java. You can select both Maven or Gradle. Generate the project, download it, extract it into local disk.
$ mkdir microdemo $ cd microdemo/ microdemo$ unzip ~/Downloads/microdemo.zip microdemo$ JAVA_HOME=/jdk-14 mvn install
2. Open the microdemo
folder in VSCode
3. Wait for message "Indexing completed" and then you can enjoy editing, code completion and other NetBeans goodies
Plus your VSCode now supports all the latest and greatest JDK14 coding structure:
var running = application.isRunning(); Assertions.assertTrue(running);
Can your VSCode do that with the RedHat extension on JDK 8? If not, install the Apache NetBeans VSCode extension!
Scenario 2: Polyglot Debugging
In this sample we will go over how to create and debug Java <> JavaScript polyglot project using JDK 11, Graal.JS, and ready to go sample:
graal-js-jdk11-maven-demo Maven Archetype
The sample is a simple Java application invoking in a loop fibonaci calculation for incremented number written in JavaScript.
Complete sample is attached below for your convenience.
Set Up
- Clone sample repository and move to the newly cloned directory.
- Make sure that
JAVA_HOME
points at a JDK11 (or later)export JAVA_HOME=/path/to/jdk11.
- Although this archetype is named *jdk11* it can be used with JDK 8 as well, just set to both variables
JAVA_HOME
andnetbeans.jdkhome
to your JDK8 home.
- Although this archetype is named *jdk11* it can be used with JDK 8 as well, just set to both variables
- In VS Code, go to Preferences | Settings, search for
netbeans.jdkhome
, and set it to/path/to/jdk11
(or later). - Open Folder with
graal-js-jdk11-maven-demo
in VSCode. - Remove
App.java
andAppTest.java
originally coming with the sample Maven project.
Development
In
main/java/com/mycompany/app
, add a new file namedPolyglotSample.java
with the following code:- Create the following structure to store the JS source file, so that Java can find it, within the
main
folder:resources/com/mycompany/app
In this
resources/com/mycompany/app
folder, create a file namedfib.js
and paste in the following JS code:- Save all files and invoke action from Command Palette: Java: Compile Workspace.
Note:- This is an action provided by VSNetBeans which builds the project.
- The project is also built when the debugger starts, but it is worth checking before the first debug session to make sure that the Maven build passes.
Once the build succeeds, let's test the project.
Testing
- Set breakpoint to line 11 in fib.js and
- Select F5 to launch debugger and select type
Java 8+
which is VSNetBeans provided debugger for JDK 8 and Polyglot capable of debugging Java and scripting languages like Graal.JS impl. of JS. - When started you should see something like following screenshot with Call Stack from JS to Java and variables from JS and Java depending on what context you have currently stepped into.
The modified graal-js-jdk11-maven-demo is available for your convenience as:
$ git clone https://github.com/JaroslavTulach/graal-js-jdk11-maven-demo $ cd graal-js-jdk11-maven-demo $ git checkout Fibonacci
Happy Polyglot development and debugging with VSNetBeans!
Scenario 3: Open OpenJDK Source
The OpenJDK sources can be directly open in VS Code using VSNetBeans.
SetUp
Follow these steps to prepare the OpenJDK sources:
- Clone the OpenJDK from https://github.com/openjdk/jdk
- configure using
bash configure,
and provide a path to jtreg, like using the--with-jtreg=<JTREG_HOME>
option - build the JDK using
make images
Open Sources
To open an OpenJDK module inside VS Code, open the src/<module-name>
directory. For example, to open the most basic java.base
module, open src/java.base
. When opening the first module, use File/Open Folder...
, to open additional modules and/or tests, using File/Add Folder To Workspace...
. Tests are typically in either the test/jdk
or test/langtools
folder.
After opening the folders, it is recommended to wait for the "Indexing Complete." messages in the status line.
Then, enjoy browsing and editing the OpenJDK sources!
Scenario 4: GraalVM Sources
Get the Graal repository (or related repositories like Graal.js, Graal Python, etc.) and prepare it for development (most importantly make sure the mx tool is PATH
). Then select a suite (graal/sdk
, graal/truffle
, graal/compiler, etc.
) and build it using mx build
. Then open the suite in code
as a folder (_File/Open Folder_). With for the Apache NetBeans Language Server extension to be initialized (shows Indexing finished in the status line). Use Ctrl-O to open any Java file. Edit, use code completions provided by the system, open tests, run and debug them. Open a test class, locate @Test
method to debug and choose Debug :
The system invokes mx build
and mx unittest ...
automatically for you and connects debugger to the started JVM. Then it's up to you to step through the code, hit breakpoints, etc. Should you debug Truffle language (like JavaScript, Python, etc.), the debugger steps in and shows you the guest language statements - see scenario 2 for more details.
Should you need to explicitly build from the code
choose Ctrl+Shift-P and type Java: Compile Workspace - that invokes mx build
.