Eclipse View JDK Source code

The settings for introducing JDK source code in eclipse:

Settings:

1. Point "Window", "Preferences", "Java", "Installed JREs"

2. The right side of "Installed JREs" is the list pane, listing the JRE environment in the system, selecting your JRE, and then clicking "Edit ..." on the edge, a window will appear (edit JRE)

3. Select this entry for the Rt.jar file: "C:\Program Files\java\jre_1.8.0_0\lib\rt.jar" (depending on your JRE path)
Point to the left of the "+" sign to expand it,

4. After expanding, you can see "source Attachment: (None)", point this item, point to the right button "Source Attachment ...", select "Src.zip" file under your JDK directory

5. "OK", end.

Dt.jar is a class library about the operating environment, mainly swing packages
Tools.jar is a class library of some tools
Rt.jar contains the base class library of the JDK, which is the class file of all the classes you see in Java doc

Eclipse View JDK Source code