Set value in Map while debugging in IntelliJ Idea

Question

While debugging I would like to change value in HashMap (map name: params). There is: "charset" -> "ISO-8859-1". When I try to set value (F2) and type: "charset" -> "UTF-8" then error message is: Invalid expression : ->. When I try to open "charset" -> "ISO-8859-1" then there is:

key = "charset" 
value = "ISO-8859-1"

but set value (F2) on value = "ISO-8859-1" doesn't work, it's greyed out. When I open "value"="ISO-8859-1" then I see:

value={char[10]31444}
hash=20129143423

Is there a chance to change value in HashMap to set some different value instead of ISO-8859-1 which already is there.

Answer 1

Open "Evaluate" window (Alt+F8) and type a normal code to put a new value into the map:

params.put("charset", "UTF-8")