How do I add an action to a project node’s popup menu of my own project type?

To add the Copy/Delete/Move/Rename action to your project’s node, you should:
1. Implement the corresponding interface such as org.netbeans.spi.project.CopyOperationImplementation.
2. Implement org.netbeans.spi.project.ActionProvider:

public final class AddActionActions implements ActionProvider {
    private final AddActionProject project; //suppose this is your project
    public AddActionActions(AddActionProject project) {
        this.project = project;
    }
    public String[] getSupportedActions() {
        return new String[] {
            ActionProvider.COMMAND_COPY
        };
    }
    public boolean isActionEnabled(String command, Lookup context) {
        if (command.equals(ActionProvider.COMMAND_COPY)) {
            return true;
        } else {
            throw new IllegalArgumentException(command);
        }
    }
    public void invokeAction(String command, Lookup context) {
        if (command.equalsIgnoreCase(ActionProvider.COMMAND_COPY)){
            DefaultProjectOperations.performDefaultCopyOperation(project);
        }
    }
}

1. Add these implementations to your project’s lookup:

lookup = Lookups.fixed(
    // ... as before
    new AddActionOperation(this),
    new AddActionActions(this),
);

1. Register the actions into the project node’s context menu:

public @Override Action[] getActions(boolean context) {
    Action[[ | ]] nodeActions = new Action[2];
    nodeActions[0] = CommonProjectActions.copyProjectAction();
    nodeActions[1] = CommonProjectActions.closeProjectAction();
    return nodeActions;
}

To add the other actions specified in the Project API such as closeProjectAction, just add it to the list of actions of your node.
To add an action you created yourself, just add it to the list of actions of your node.

Apache NetBeans 23

How do I add an action to a project node’s popup menu of my own project type?