Q:

IntelliJ can't display big file? 

My text file is 1.58G, my IntelliJ custom VM options is set as "-Xmx4G".  Why does it shows 
"The file is too large; 1.58G. Showing a read-only of the first 2.56M". 

A:

idea.properties file contains the default limits for the files IntelliJ IDEA can handle:
#---------------------------------------------------------------------
# Maximum file size (kilobytes) IDE should provide code assistance for. 
# The larger file is the slower its editor works and higher overall system memory requirements are
# if code assistance is enabled.  Remove this property or set to very large number if you need
# code assistance for any files available regardless their size. 
#---------------------------------------------------------------------
idea.max.intellisense.filesize=2500

#---------------------------------------------------------------------
# Maximum file size (kilobytes) IDE is able to open. 
#---------------------------------------------------------------------
idea.max.content.load.filesize=20000

These can be changed using Help | Edit Custom Properties.