How to stop IntelliJ IDEA from modifying the Java source code?

Hi All,
I'm learning Java and so I use to view the source codes of the Java API source files along with coding in Java.

Problem:
The IDE is modifying the view of the source code for convenience.

Question:
I want to see the actual unmodified version of the source codes. Is there any a way I can stop the IDE from modifying the view of the source code automatically?

Temporary solution:
I'm copying the path of the source files and opening them in a plain text editor to view the original source code. 

Supporting attachments:
Screenshots of the modified and unmodified versions of the same source file:

1.  Source: "Java\jdk1.8.0_162\src.zip!\java\nio\channels\FileChannel.java"
  Inside IDE (IntelliJ IDEA):
  Outside IDE (Notepad++):


2.  Source: "Java\jdk1.8.0_162\src.zip!\java\nio\channels\FileChannel.java"
  Inside IDE (IntelliJ IDEA):

  Outside IDE (Notepad++):


3.  Source: "Example.java" (My own source file)
  Inside IDE (IntelliJ IDEA):

  Outside IDE (Notepad++):

Request:
In case of any setting/preference change in the IDE please mention the path clearly else please provide a detailed reason and resolution of the issue, if present.

Thank you in advance. Have a nice life!