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How can I make a resizable GUI with Java swing?

Hi :) I'm making my first GUI with Java swing, and I have a problem: when I change window dimension, "internal components" don't change their size.
I use absolute layout, it may be an important thing to know.

Absolute layout means that you are using absolutely defined constraints about position size e.t.c. To create resizable GUI. you need to use more "flexible" layouts.
One simple option to start is BorderLayout. Hovewer you have to leverage use of panels in this case.
Documentation
Another possibility may be the Grid bag layout but that often involves more work to do.

You can solve this problem by using the MigLayout in combination with the WindowsBuilder. This is a WYSIWIG editor for SWT and Swing Layouts. But BorderLayout and GridBag Layout can srink and grow as well.

Resize JFrame and Components Based On Computer Resoultion

I've made a java application in netbeans and am wondering how to have the size of the jframe half the width and height of the computer resolution and also having the components comply with this change. I tried putting code and it did make the frame half the height of the computer resolution but my components, such as buttons and textfields, stopped showing. How can I achieve this? Thanks.

(EDITED)
Set the JFrame's layout manager to GridLayout. In the properties window of the GridLayout itself (select in the navigator window) set columns to 1 and rows to 2. This should give you what you want and you won't have to get into the code.
This is the key code being called within the initComponents() method of your JFrame subclass (created by NetBeans) but it is important to understand where it is:
getContentPane().setLayout(new java.awt.GridLayout(2, 1));
I love Netbeans but you do have to understand the basics.
Good luck with your project. Swing is an awesome toolset that was way ahead of it's time.

As usual in this situation the key is using the right combination of layout managers for your containers. You're probably using NetBeans generated code (something I recommend you avoid until you are very comfortable with Swing coding), and it's probably having you use GroupLayout, a fine layout, but one that might not behave as well as you'd like on resizing components. I suggest that you go through the layout manager tutorial and try to nest JPanel containers and play with different layouts that re-size well such as GridLayout, GridBagLayout and BorderLayout to try to create the best layout that can re-size well.

How to enlarge java swing panel

I create some panel with a lot of components as images text ... . Now I have one problem. Customers tell me that panel is too small. Is there some option to enlarge this whole panel or I have to enlarged components one by one ?
UPDATE:
from this:
to this:

everything depends of used LayoutManager,
Is there some option to enlarge this whole panel or I have to enlarged
components one by one
-> no, basically this is reason why LayoutManager exists there, most of them there are created especially for this reasons, GridLayout, GridBagLayout, BoxLayout (maybe without glue), BorderLayout and todays MigLayout are best way how to do it

it depends, if you have a GridLayout or some Layout witch set all the components with some order, for example, all the components at the same distance or all the components like a Matrix, if you enlarge the panel, all the components will enlarge with it. If not, you have to enlarge by hand.

Auto resize swing elements to fit to the container's size

Not sure if what I need is possible.
I have a container (JPanel) that contains some internal elements.
I was wondering if it is possible to force internal elements to fit into the container's size.
I need them to be fully visible i.e., resize to fit inside the Panel's size and not cut some parts of the internal elements.
Scrolling is not an option.
Is this possible by using a Layout or something?
EDIT: Important clarification:
The thing is that I do not have access to the internal elements neither to their properties so I would say that a Layoutmanager capable of resizing child elements to fit to its size is needed. I tested BorderLayout and GridBagLayout but the result is always the same, the internal elements are cut out.

It's for exactly that reason that LayoutManagers exist. All the LayoutManagers work for simple containers directly, excluding GridBagLayout which is to able to handle most complete GUIs directly.
For most complete GUI's you have some choices as follows:
Look for a 3rd party layout such as MigLayout or here
Use GridBagLayout
Very easy way is use nested layout, where there is more than one JPanel and each has child JPanels with the same or different LayoutManager
Or custom layout, should be hard..., but same as using GridBagLayout

You could set the JPanel layout to border layout, then add the single child to the center. If there are multiple children, this approach becomes less useful since components added to the the NORTH, SOUTH, EAST, and WEST will remain statically sized while the centre resizes to fill the remainder.
In short, this isn't an ideal solution. All layouting in Swing is made all the more complex by the fact that different components behave in different ways, so you really need to provide further details of the child components you wish to add to your panel, and any behaviour that has been overridden on those components.
The best way is to try a couple of simple examples to see what mileage you get and whether subtle redesign of your child component nesting could help.

you can use a layout, like GridBagLayout, or BorderLayout depending on the situation. With proper weights it is possible.

this sounds to me like you should just peek an appropriate layout manager and use it. For example, look at BorderLayout - put your component in the CENTER and it will occupy all the area. Its up to each concrete layout manager to decide what will be the size of the components.
Mark

I was using a JInternalFrame inside JDesktopPane. I wanted the internal_frame to auto resize as desktop pane is resized, so I had to implement the AncestorResized event for the internal frame where I placed the following code:
this.setPreferredSize(this.getParent().getPreferredSize());
this.pack();

Swing: Is there a simple way to make 1 component ignore the layout manager?

I have a JPanel with one component that I want to place in an absolute sense, whereas the rest of the components are placed according to a layout manager.
Is there a simple way to do this?

Are you saying you want a component painted over top of all the other components? If so then you would need to use a JLayeredPane.
Why don't you post a SSCCE that demonstrates what you want to do?
You can add components to a frame as you would do normally and make the frame visible. Then you can add this random component and use setBounds on the component. As long as you don't revalidate() the panel or resize the frame we will be able to see how you intend to position this component relative to all the other components.

You might also want to look at OverlayLayout, seen here. For some reason it's excluded from the conventional gallery, but it may be of interest.

You can do this with only needing one JPanel using MigLayout