# Apache NetBeans Language Server Extension for VS Code

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This is a technology preview of [Apache NetBeans](http://netbeans.org)
based extension for VS Code. Use it to get all the _goodies of NetBeans_
via the VS Code user interface! Runs on __JDK8__[*] and all newer versions.

Apache NetBeans Language Server brings full featured Java development (edit-compile-debug & test cycle) for Maven and Gradle projects to VSCode. As well as other features.
## Getting Started
1. Set JDK in `VSCode | Preferences | Settings ...` __Netbeans: Jdkhome__ setting to point to JDK which Language Server will run on and projects will be compiled with. More below in section [Selecting the JDK](#selecting-the-jdk)

2. Use __Java: New Project...__ " command to start creating new project, or
3. Open the folder with existing __pom.xml__ for Maven or ___Gradle___ project files (_build.gradle, gradle.properties_).
    *  Language Server opens the project, performs priming build and might ask for Resolving problems, usually related to opening 
    subprojects etc.
4. Or simply create a new Java class file with `public static void main(String[] args)` method in opened folder and start coding, compiling, debugging. Works on JDK 8 and newer.


## Supported Actions
* __Java: New Project...__ allows creation of new Maven or Gradle project 
* __Java: New from Template...__ add various files to currently selected open project. Files are:
    * Java - broad selection of various predefined Java classes
    * Unit tests - JUnit and TestNB templates for test suites and test cases
    * HTML5/JavaScript - Templates for JS, HTML, CSS,... files
    * Other - various templates for JSON, YAML, properties, ... files
* __Java: Compile Workspace__ - invoke Maven or Gradle build
* Debugger __Java 8+...__ - start main class or test on JDK8+. More in [Debugger section](#debugger-and-launch-configurations)
* Progress shown for long running operations with cancel support for selected types
* __Native Image Debugger__ is a new Run configuration added which allows Java style debugging of Ahead of Time compiled native-images, produced by GraalVM. It is experimental feature which works with GDB on Linux. GDB 7.11 or GDB 10.1+ is required due to known issue [#26139](https://sourceware.org/bugzilla/show_bug.cgi?id=26139) in GDB 8 and 9.
* __Micronaut and Spring__ support especially for YAML configuration files with code completion and source code navigation to Java.
* __Test Explorer__ for Java tests results visualization and execution including editor code Lenses.
* Maven and Gradle support including multi-project projects, subprojects opening and Gradle priming builds.

## Debugger and Launch Configurations
Language Server __Java 8+ ...__ launch configuration supports debugging and running Java applications using JDK8 or newer. 
1. The launch configuration (debugger) is invoked when `Run main | Debug main` code lense is selected in the code.
2. Or __Java 8+...__ is selected in __Run and Debug__ activity panel.
![Debug configurations](images/debuggers.png)
### Launch Configurations
* __Launch Java 8+ App__ - Debug or Run current Java project
* __Launch Java: Continuous Mode__ - Runs Micronaut project and reloads it when source code has been changed.
* __Attach to Port__ & __Attach to Process__ - Attach debugger actions. Available when __Java 8+ ...__ at the bottom of drop down list is selected.
    * Select this configuration, then click the ![Run](images/run.png) 
    * Select either from available process or enter the port to connect to JVM running with JDWP.
    * __Attach to Shared Memory__ is available on Windows in addtion to above mentioned _Attach..._

Default launch configurations provided by Language Server can modified in `launch.json` file using intellisense for available options.
## Supported Refactorings

Class level refactorings as well as variable refactorings are supported in VSCode via Apache NetBeans extension. See following screenshots:

![Class Source Actions](images/Source_actions.png) ![Introduce ... refactoring](images/Introduce_refactoring.png)

Some refactorings are two steps with like Override method ... where method to be overriden is selected in 2nd step:

![Override refactoring](images/Override_refactoring.png)

## Test Explorer
NetBeans Language Server provides Test Explorer view which allows to run all tests in a project, examine the results, go to source code and  run particular test.
![Test Explorer](images/Test_explorer.png)


## Native Image Debugger
Experimental Support

NetBeans Language Server allows Java like debugging of native images produced by GraalVM EE native-image tool. It is provided using GDB and via new Run configuration named __Launch Native Image__. This experimental feature works __now__ only on Linux with certain version of GDB, see above. GraalVM Enterprise Edition is needed as it produces full debug information for native images, at this time.

In order to debug native image applications it is necessary to build such native image with debug information available. It can be done by providing following switches for native-image tool: 
- `-g -O0` or 
- `-H:Debug=2 -H:Optimize=0`. 

### Using Native Image Maven Plugin
It is possible to use [Native-Image Maven Plugin](https://www.graalvm.org/reference-manual/native-image/NativeImageMavenPlugin/) to run native-image builds for Maven projects. 
In this case add following `<buildArgs>` into plugin `<configuration>`:
```
<buildArgs>
  <buildArg>-g</buildArg>
  <buildArg>-O0</buildArg>
</buildArgs>
```
Setting project's Maven pom.xml to skip native-image build everytime when project is being built is a good practice.

When native image is built, including debug info then add __Launch Native Image__ configuration to launch.json. Select it in Run & Debug activity window and press F5 to debug Java source code on native image.

## Supported Options

* __netbeans.jdkhome__ - path to the JDK, see dedicated section below
* __netbeans.verbose__ - enables verbose extension logging
* __netbeans.conflict.check__ - avoid conflicts with other Java extensions, see below

## Selecting the JDK

The user projects are built, run and debugged using the same JDK which runs the
Apache NetBeans Language Server. The JDK is being searched in
following locations:

- `netbeans.jdkhome` setting (workspace then user settings)
- `java.home` setting (workspace then user settings)
- `JDK_HOME` environment variable
- `JAVA_HOME` environment variable
- current system path

As soon as one of the settings is changed, the Language Server is restarted.

## Conflicts with other Java Extensions

Apache NetBeans Language Server extension isn't the only Java supporting
extension. To avoid duplicated code completion and other misleading clashes
the extension disables certain functionality known to cause problems, this is done per __Workspace__. 

This behavior can be disabled by setting `netbeans.conflict.check` setting to `false`.

## Contributing

Read [building instructions](BUILD.md) to help Apache community to
improve the extension.