I couldn't find a way to do this without copying each method, I know it can be done automatically but I'm not sure if this extension can do this.
Any help is much appreciated :)
We're not there yet. We need a Code Action to implement missing methods. (See jdt.ls#169).
The least bad alternative right now is to use content assist to override each method. The method body will be generated.

@yaohaizh is this something you or someone from your team could address? It's an important usability feature.
cc @akaroml
@fbricon No problem, I talked about this issue with @aeschli before and would like to add this code action.
@yaohaizh PR works really well

we should be able to merge it once you fix the couple issues I mentioned in my review.
New code action is available in the latest CI build. You can get the most recent java-<version>.vsix file from http://download.jboss.org/jbosstools/jdt.ls/staging/ and install it by following the instructions here.
Be aware though, for the moment, the implemented methods use tab indentation by default (see https://github.com/Microsoft/vscode/issues/32158).
If you use spaces for indentation instead and enabled automatic format on save ("editor.formatOnSave": true), then tabs will be replaced by spaces when the file is saved.
Alternatively, you can add the following to your project's .settings/org.eclipse.jdt.core.prefs:
org.eclipse.jdt.core.formatter.tabulation.char=space
org.eclipse.jdt.core.formatter.tabulation.size=4
How to use this feature? I could not find the Add unimplemented methods button in my editor
VSCode version:1.29.1
Language Support for Java(TM) by Red Hat version: 0.35.0
@kdlan See this :

@yaohaizh
It works. Thanks
Most helpful comment
Be aware though, for the moment, the implemented methods use tab indentation by default (see https://github.com/Microsoft/vscode/issues/32158).
If you use spaces for indentation instead and enabled automatic format on save (
"editor.formatOnSave": true), then tabs will be replaced by spaces when the file is saved.Alternatively, you can add the following to your project's
.settings/org.eclipse.jdt.core.prefs: