IDE support in the JDK

## Introduction

When you are familiar with building and testing the JDK, you may want to configure an IDE to work with the source code. The instructions differ a bit depending on whether you are interested in working with the native (C/C++) or the Java code.

### IDE support for native code

There are a few ways to generate IDE configuration for the native sources, depending on which IDE to use.

#### Visual Studio Code

The make system can generate a Visual Studio Code workspace that has C/C++ source indexing configured correctly, as well as launcher targets for tests and the Java launcher. After configuring, a workspace for the configuration can be generated using:

    make vscode-project

This creates a file called `jdk.code-workspace` in the build output folder. The full location will be printed after the workspace has been generated. To use it, choose `File -> Open Workspace...` in Visual Studio Code.

##### Alternative indexers

The main `vscode-project` target configures the default C++ support in Visual Studio Code. There are also other source indexers that can be installed, that may provide additional features. It's currently possible to generate configuration for two such indexers, clangd and rtags. These can be configured by appending the name of the indexer to the make target, such as:

    make vscode-project-clangd

Additional instructions for configuring the given indexer will be displayed after the workspace has been generated.

#### Visual Studio

This section is a work in progress.

    make ide-project

#### Compilation Database

The make system can generate generic native code indexing support in the form of a Compilation Database that can be used by many different IDEs and source code indexers.

    make compile-commands

It's also possible to generate the Compilation Database for the HotSpot source code only, which is a bit faster as it includes less information.

    make compile-commands-hotspot

### IDE support for Java code

This section is a work in progress.