swing | Configuration switcher by an environment variable

I have 3 tables but they have been merged into one dataframe for this example.

1. Account Information with Interest Rate Conditions (first 5 columns of df). These rates are the actual rates applied to the accounts and need to be matched off to ensure they were set up correctly
2. Non Std Rates - Certain accounts will apply these non-std rates once certain conditions are met
3. Std Rates- Same as above these will apply once certain conditions are met

I scanned JDK source code to see whether there was a definitive answer (see below) and a few other SO posts which suggest:

Result with xprop | grep -i name when LANG=C.utf8

Sidebar is just the sidebar for the application with buttons

Content is the main content of the app

Content sidebar is a side bar inside of content, I use this so my settings page has its own side bar apart from the normal side bar.

I make sidebar aligned to WEST and content CENTER

after content.add(contentSidebar, BorderLayout.WEST); it won't make content sidebar go to west and im not sure why.

this is my source code

I just made a brand new project and want to load content as the window open, I have a JFrame with a JPanel(swing), i've tested many things until I found that windowOpened is the equivalent of the onload method from C#, the problem comes when trying to use this event to load content, after many tries I didn't get anything so I went to the basic and called a System.out.print("Test");.

The JFrame loaded succesfully but the message didn't show up in the console ultil I closed the window, then added a button to play around and added the same print and when clicking the button I got nothing in the console until I spammed it like 5 to 6 times, kind of weird so I added a showMessageDialog after the print and to my surprise the messagedialog works as expected but the print is still not working until I spam it many times.

This is my third brand new project trying to load content but all of them seems to work the same way, is it a problem with my computer or this is a normal behavior for java? can I change this behavior? what is the correct way to do this?

Here is the console logs:

Essentially, for anyone familiar with WinForms, it should be as if the left "table" were anchored top, left, and bottom, and the right table were anchored top, right, and bottom.

The first thing I tried was a FlowLayout, but the tables would not resize properly as the window was resized.

To create the two tables and central button between them, I experimented with BorderLayout, by putting the tables in EAST and WEST and the button in the CENTER region. That succeeded in having the two tables being appropriately sized and resized as the window is resized, however the button filled up the entire space between them, and the width changed as it was resized (I want it to stay constant).

Any ideas to get me started?