This is the second release of the javaUML extention
Save settings for extention uniqly for each project

Convert Java project into plantUML class diagram

Convert plantUML file into a Java project

Add classes or method and fields to existing classes in the plantUML file then those will be added to the Java project without deleting existing code

Install extention, duh
Open a java project
Open up the JavaUML view in the side bar
Select the source folder of your project
Select the output folder (where ever you want your plantUML file to be created)
Create diagrams and java project
Select and deselect difrent features such as contains arrows