Eclipse IDE for Java developers version: 2019-03 (4.11.0), there is no automatic prompt function, that is, when an object can’t point out its related methods. Later, I searched the Internet, and the summary method is.

1. My window – & gt; Preferences-> Java-> Editor-> content assist  
put   Enable auto activation   Check the options: (as shown in the figure below)

And add. Abcdefghijklmnopqrstuvwxyz after the point

At this point, the restart of eclipse is not successful, and then the second step

 
 
2. Tick the bucket that should be checked

My own eclipse was successful without a restart.

To sum up, the role of the first step is that when you enter a letter, eclipse will immediately associate the relevant words and display them, and those associated words will always follow. If you feel bored, change to the default dot. The second step is the key, the role is when you use Alt +/shortcut key will associate.