12c Jdeveloper - Modify Jdeveloper font size

In order to set the font size for the Jdeveloper IDE,  you need to modify the ide.properties file to set the font size.

It is typically available under 

Windows: Go to the following location

For 11g:

C:\Users\{user_name}\AppData\Roaming\JDeveloper\system11.<Versiopn>\o.jdeveloper\ide.properties

For 12c:

C:\Users\{user_name}\AppData\Roaming\JDeveloper\system12.<Versiopn>\o.jdeveloper\ide.properties

# To modify the font size for all look-and-feels in all locales, set

# the Ide.FontSize property.  For example:

# Ide.FontSize=11

Change to:

(remove only the comments and provide your desired value for font size):

Ide.FontSize=16

In fact the ide.properties file is so self explanatory it has lot of comments documented in it on how to set the font sizes for a specific locale and look and feel etc.