Q:

GridBagLayout troubles

I'm trying to make simple game layout. 
I make my layout from Containers - all containers are similar to my example(it mean JPanel, setlayout, add components, return JPanel). 
Structure of whole Layout: (this 3 are in main layout)
upper - BorderLayout. PAGE_START; //menu
center - BorderLayout. PAGE_CENTER; //centerContainer()
bottom - BorderLayout. PAGE_END; //statusBar - just container with text

placement of this 3 containers works fine, but problem is with placement in the centerContainer. 
Center container structure: 3 containers - aboutServerContainer, aboutGameContainer, gameContainer. 
gameContainer has size 450x450
I want to start serveInfo in same height as gameContainer and gameInfo under serverInfo, 
but it somehow cernter the serverInfo and the gameInfo is uder it, but it also make free space under gameContainer (I don't want any free space here.) 

private Container centerContainer() {
        JPanel centerJPanelJP = new JPanel();
        GridBagConstraints gbc = new GridBagConstraints();
        stredniJPanelJP.setLayout(new GridBagLayout());

        //gbc.fill = GridBagConstraints. BOTH;
        gbc.gridx = 0;
        gbc.gridy = 0;
        gbc.gridheight = 1;
        centerJPanelJP.add(aboutServerContainer(),gbc);

        gbc.gridheight = 1;
        gbc.gridy = 1;
        centerJPanelJP.add(aboutGameContainer(),gbc);

        gbc.gridheight = 2;
        gbc.gridx = 0;
        gbc.gridy = 0;
        centerJPanelJP.add(gamePanelContainer(),gbc);

        return centerJPanelJP;
    }

A:

It looks like you are trying to achieve a layout like this:
+-----+-----+
|  A  |     |
+-----+  C  |
|  B  |     |
+-----+-----+

To achieve that, you grid constraints should be as:
  |  x  y  width  height
--+---------------------
A |  0  0    1       1 
B |  0  1    1       1 
C |  1  0    1       2 

In my opinion, it is better to consistently use a "powerful" layout manager, than to deal with special cases, nested panels and inflexibility of lining things up.