For long time, I was using Netbeans to develop Swing applications because it has WYSIWYG feature and to be honest I was not aware (lazy to search) that Eclipse has this feature or not. Finally, lately, I did a simple search on the internet and found out that Eclipse had WindowBuilder which is more or less equal to Netbeans Swing designer and you just need to install the package to be able to create Swing applications.
I have found the following Youtube video tutorial is quite useful and if you want to know how to install Eclipse WindowBuilder I recommend you to watch it. It is also good to subscribe the channel since it is merely dedicated to programming and you can find lots of useful and awesome materials.
Note : If you have already made a Swing application and you just want to open it inside of Eclipse in visual form just right click on your Java file and click on open with WindowBuilder Editor.