.RU File Extension
File TypeJava Russian Font Properties File
What is a RU file?
Settings file used by Java applications; contains mappings between logical font names in the Java program and the actual fonts on the computer system; specifies fonts that contain Russian glyphs to be used by the program, instead of the standard Latin fonts.
RU Java font properties files have the filename font.properties.ru. They are Java .PROPERTIES files that are loaded by the Java Virtual Machine (JVM) at runtime. The settings stored in the font properties files are available to the Java program using the java.util.Properties API.
NOTE: Russian websites use the ".ru" domain suffix, which should not be confused with the ".ru" file extension.