Developing Java Applications with Visual Studio Code
Speaker: Fred Bricon
@fbricon

For more blog posts, see The Oracle Code One table of contents

VS Code

• Lightweight extensible “source code editor”
• Open source
• Developed by Microsoft, but vibrant community
• Led by Erich Gamma (Gang of Four and one of the original authors of Eclipse)

Language Server Protocol

• language specific smarts
• standard protocol to minimize effort to support multiple development tools/languages
• open source protocol
• development led by microsoft
• JSON RPC 2.0 messages
• tool opens/edits docs/displays errors. language server initializes languages tools/identify compilation error/etc.

Eclipse JDT.LS

• Implemented language server for Java in Java.
• Running language server launches headless Eclipse behinds scenes
• Adds custom commands
• Extensible through OSGi bundles

Vs Code – Java

• RedHat developed thin wrapper.
• Launched late 2016
• Updates about twice a month
• Half a million extensions
• Other Java tools
  • debugger (from MS)
  • test runner (from MS)
  • Fabric8 analytics
  • java decompiler
  • lombok support
  • checkstyle
  • maven
  • dependency analytics – new plugin to flag components with CVEs. Plugin not completely ready. Not all CVEs loaded yet. Just something to play with at this point.
• VS Code LiveShare – plugin where can share content of workspace with up to 50 people. They can even set breakpoints in your workspace.

Next steps

• Better refactoring support
• Quick fixes from problems view
• Huge backlog; more improvements soon

Demo

Note: I have a bunch of notes to myself of things I want to try. I also want to ask Thomas for a copy of his workspace preferences file. It seems more reasonable than the defaults.

• Autocompletion
• Lightbulb with option to run/debug – have to turn on code lens in workspace settings
• Click triangle in bottom left corner to see problems/output/debug console view at bottom
• F2 = rename variable [command F2 on Mac]
• Debugger on left view on screen
• Showed hiding . files . Preference > settings. Edit workspace settings to control Ant style patterns on what see. (Edit settings as json)
• New Java Dependencies plugin. Came out recently. Can see Maven dependencies
• Command shift o – see outline in file [want to try; didn’t work on first shot]
• command p – list all files in project
• Command click – navigate into class [want to try; didn’t work on first shot]
• Organize imports – alt shift o
• Saving gives instant feedback – need to turn on
• Run test runner. Code lens shows red/green test status in class itself.
• Can type “get” and getters are suggested (vs typing them in)
• Showed changing code while app is running
• Using a bad dependency gives CVE error in problems view

My take: FRC (FIRST Robotics Competition) teams are using VS Code this year. I’ve learned a little but am nowhere near fluent. So was really looking forward to the demo. Plus hearing the story of how the plugins came to be is interesting. But seeing someone use it who is comfortable with the tool is even more valuable.