Question: I am working on a GWT application.

I want to convert a hashMap to JSON String and send it to GWT server

My HashMap is like `HashMap<String, CustomProperties)`

CustomProperties is the class with different parameters. This HashMap is property of file .

I want to uplaod a file with these properties.

What I am going to do : Attach the json Sting to hidden field and send it with the file through the formPanel.

But I dont know how to do Hashmap to JSON String.

Can anyone guide me in this regard ?

Answer: 
If you know the user that installed the trigger you could ask them to do to the "All my triggers" menu item in the script editor, find the trigger and delete it.
In the on-error email, there is a link to manage triggers. Make sure that the triggers are really gone. I had this issue with a set of shared spreadsheets, where I thought I had removed all the triggers, but my partner still had some enabled.