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JScrollPane components do not appear

I'm trying to put some components inside of a JScrollPane but every time I launch my program they don't appear. I just started learning about GUIs today so I figure I missed something small but no matter where I look online I can't find an answer. The only thing that appears is the JScrollPane itself.
class MainFrame extends JFrame{
public MainFrame(String title){
//Main Frame Stuff
super(title);
setSize(655, 480);
setDefaultCloseOperation(DO_NOTHING_ON_CLOSE);
//Layout
FlowLayout flow = new FlowLayout();
setLayout(flow);
//Components
JButton spam_button = new JButton("Print");
JLabel label = new JLabel("What do you want to print?",
JLabel.LEFT);
JTextField user_input = new JTextField("Type Here", 20);
//Scroll Pane
JScrollPane scroll_pane = new JScrollPane(
ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS,
ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
scroll_pane.setPreferredSize(new Dimension(640, 390));
//Adding to Scroll
scroll_pane.add(label);
scroll_pane.add(user_input);
scroll_pane.add(spam_button);
//Adding to the Main Frame
add(scroll_pane);
//Visibility
setVisible(true);
}
}
The point of the program is to print whatever you type 100 times but I haven't gotten that far yet because I've been hung up on this scroll problem. When I finally get things to show up in the scroll pane I'm going to move those three components to a JPanel above the scroll pane and then I'm going to add the 100 words to the scroll pane so that you can scroll through it.

I just started learning about GUIs today
So the first place to start is with the Swing tutorial. There is plenty of demo code to download and test and modify.
scroll_pane.add(label);
scroll_pane.add(user_input);
scroll_pane.add(spam_button);
A JScrollPane is not like a JPanel:
you don't add components directly to the scroll panel. You add a component to the viewport of the scroll pane
only a single component can be added to the viewport.
So your code should be something like:
JPanel panel = new JPanel();
panel.add(label);
panel.add(user_input);
panel.add(spam_button);
scrollPane.setViewportView( panel );

How to fix a JButton to not take up the whole JFrame

I am a beginner in coding and I am learning Java. I'm busy making a log in system, and I have made a JFrame, but when I add a JButton, it takes up the whole JFrame.
public class LogInSystem extends Application{
#Override
public void start(Stage primaryStage)
{
// Setting the JFrame
JFrame frame = new JFrame("Log in System");
frame.setSize(2000, 2000);
frame.setVisible(true);
// Setting the button
JPanel panel = new JPanel();
Button btn1 = new Button();
btn1.setText("1");
btn1.setBounds(50, 150, 100, 30);
frame.add(btn1);
frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
}
}

It seems like you declare a panel and not adding button into it as well as not adding the panel to the frame. You can try to add your button into panel and panel into frame,
panel.add(btn1);
frame.add(panel);
You can also use some useful layout for a particular panel. For example, BoxLayout, GridLayout and etc. By default, everything is set to be FlowLayout.

Problems with BorderLayout() in Java

I've tried a lot of different ways, but I will explain two and what was happening (no error messages or anything, just not showing up like they should or just not showing up at all):
First, I created a JPanel called layout and set it as a BorderLayout. Here is a snippet of how I made it look:
JPanel layout = new JPanel();
layout.setLayout(new BorderLayout());
colorChoice = new JLabel("Choose your color: ");
layout.add(colorChoice, BorderLayout.NORTH);
colorBox = new JComboBox(fireworkColors);
colorBox.addActionListener(this);
layout.add(colorBox, BorderLayout.NORTH);
In this scenario what happens is they don't show up at all. It just continues on with whatever else I added.
So then I just tried setLayout(new BorderLayout()); Here is a snippet of that code:
setLayout(new BorderLayout());
colorChoice = new JLabel("Choose your color: ");
add(colorChoice, BorderLayout.NORTH);
colorBox = new JComboBox(fireworkColors);
colorBox.addActionListener(this);
add(colorBox, BorderLayout.NORTH);
In this scenario they are added, however, the width takes up the entire width of the frame and the textfield (not shown in the snippet) takes up basically everything else.
Here is what I have tried:
setPreferredSize() & setSize()
Is there something else that I am missing? Thank you.
I also should note that this is a separate class and there is no main in this class. I only say this because I've extended JPanel instead of JFrame. I've seen some people extend JFrame and use JFrame, but I haven't tried it yet.

You created a JPanel, but didn't add it to any container. It won't be visible until it is added to something (a JFrame, or another panel that is in a frame somewhere up the hierarhcy)
You added two components to the same position in the BorderLayout. The last one added is the one that will occupy that position.
Update:
You do not need to extend JFrame. I never do, instead I always extend JPanel. This makes my custom components more flexible: they can be added in another panel, or they can be added to a frame.
So, to demonstrate the problem I will make an entire, small, program:
public class BadGui
{
public static void main(String[] argv)
{
final JFrame frame = new JFrame("Hello World");
final JPanel panel = new JPanel();
panel.add(new JLabel("Hello"), BorderLayout.NORTH);
panel.add(new JLabel("World"), BorderLayout.SOUTH);
frame.setVisible(true);
}
}
In this program I created a panel, but did not add it to anything so it never becomes visible.
In the next program I will fix it by adding the panel to the frame.
public class FixedGui
{
public static void main(String[] argv)
{
final JFrame frame = new JFrame("Hello World");
final JPanel panel = new JPanel();
panel.add(new JLabel("Hello"), BorderLayout.NORTH);
panel.add(new JLabel("World"), BorderLayout.SOUTH);
frame.getContentPane().add(panel);
frame.setVisible(true);
}
}
Note that in both of these, when I added something to the panel, I chose different layout parameters (one label I put in 'North' and the other in 'South').

Here is an example of a JPanel with a BorderLayout that adds a JPanel with a button and label to the "North"
public class Frames extends JFrame
{
public Frames()
{
JPanel homePanel = new JPanel(new BorderLayout());
JPanel northContainerPanel = new JPanel(new FlowLayout());
JButton yourBtn = new JButton("I Do Nothing");
JLabel yourLabel = new JLabel("I Say Stuff");
homePanel.add(northContainerPanel, BorderLayout.NORTH);
northContainerPanel.add(yourBtn);
northContainerPanel.add(yourLabel);
add(homePanel);
setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
setLocationRelativeTo(null);
setExtendedState(JFrame.MAXIMIZED_BOTH);
setTitle("Cool Stuff");
pack();
setVisible(true);
}
public static void main(String[] args)
{
SwingUtilities.invokeLater(Frames::new);
}
}

The below suggestion is assuming that your extending JFrame.
Testing
First of all, without seeing everything, theres always a numerous amount of things you can try.
First off, after you load everything, try adding this in (Again, assuming your extending JFrame:
revalidate();
repaint();
I add this into my own Swing projects all the time, as it refreshes and checks to see that everything is on the frame.
If that doesn't work, make sure that all your JComponent's are added to your JPanel, and ONLY your JPanel is on your JFrame. Your JFrame cannot sort everything out; the JPanel does that.
JPanel window = new JPanel();
JButton button = new JButton("Press me");
add(window);
window.add(button); // Notice how it's the JPanel that holds my components.
One thing though, you still add your JMenu's and what-not through your JFrame, not your JPanel.

Any other way to add scrollbar to JPanel other than JscrollPane

I have developed a desktop application. Now in that app I want to add panel with a scrollbar. I am trying using JScrollPane, but its not working.
JPanel paraJPanel = new JPanel();
JScrollPane SP_para_list = new JScrollPane(paraJPanel);
add(SP_para_list).setBounds(10,30,250,350);
This way I am adding scrollbars to panel. But it shows only empty panel with borders. It is not showing components in the panel. Although I have added several labels in it. Is it correct? Is there any other way to add scroll bar to panel.
Thanks in advance

You need to set the PreferredSize for the panel, to make the scrollbar show up, like below.
even you do not set a layout, the panel already has a default layout set.
public static void main(String[] args)
{
JFrame frame = new JFrame();
JPanel panel = new JPanel()
{
#Override
public Dimension getPreferredSize() {
return new Dimension(800, 1000);
}
};
panel.add(new JLabel("Test1"));
panel.add(new JLabel("Test2"));
frame.getContentPane().add(new JScrollPane(panel), BorderLayout.CENTER);
frame.setSize(600, 800);
frame.setVisible(true);
}

Java JPanel inside JScrollPane?

I have a JFrame, in this JFrame I have a JPanel that I draw on, this Panel can be any size and so I placed it into a JScrollpane to let me scroll when the panel is larger than the window screen size.
Unfortunately does not work as I expected:
Making the JFrame window smaller than the JPanel size does not show scroll bars
The JScrollPane size now seems locked to the size of the JPanel I have added to it, where as before it resized to the bounds of it's JFrame window (it still kinda does this but only vertically now?!)
The JPanel seems to assume the size of the JScrollpane regardless of what I set for preferred size
I am sure I'm doing something stupid, if someone could point out what I would be most grateful!
JPanel imageCanvas = new JPanel(); // 'Canvas' to draw on
JScrollPane scrollPane = new JScrollPane();
// set size of 'canvas'
imageCanvas.setMinimumSize(new Dimension(100,100));
// Scroll pane smaller then the size of the canvas so we should get scroll bars right?
scrollPane.setMinimumSize(new Dimension(50,50));
// Add a border to 'canvas'
imageCanvas.setBorder(BorderFactory.createLineBorder(new java.awt.Color(0, 0, 0)));
scrollPane.setViewportView(imageCanvas);

setPreferredSize() is the trick, setMinimumSize() and even setSize() on the component will be ignored by JScrollPane. Here's a working example using a red border.
import java.awt.*;
import javax.swing.*;
public class Scroller extends JFrame {
public Scroller() throws HeadlessException {
final JPanel panel = new JPanel();
panel.setBorder(BorderFactory.createLineBorder(Color.red));
panel.setPreferredSize(new Dimension(800, 600));
final JScrollPane scroll = new JScrollPane(panel);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLayout(new BorderLayout());
add(scroll, BorderLayout.CENTER);
setSize(300, 300);
setVisible(true);
}
public static void main(final String[] args) throws Exception {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new Scroller().setVisible(true);
}
});
}
}

// suggest a size of 'canvas'
_ImageCanvas.setPreferredSize(new Dimension(100,100));
// Scroll pane smaller then the size of the canvas so we should get scroll bars right?
_ScrollPane.setPreferredSize(new Dimension(50,50));
// ..later
_Frame.pack();

Set preferred size on the canvas.
Increase dimensions 100,100 is too small atleast on my computer.
You may want to use new GridLayout(1,1); for you JFrame if you want the scrollpane to expand when you expand the frame.

As far as I remember there are 2 options:
define the preferredSize of _ImageCanvas
create a subclass of JPanel and implement Scrollable: http://docs.oracle.com/javase/7/docs/api/javax/swing/Scrollable.html
For more details, see the Javadoc:
http://docs.oracle.com/javase/7/docs/api/javax/swing/JScrollPane.html

Check out the Scrollable interface, this may help with the sizing issues.
These two method maybe helpful:
boolean getScrollableTracksViewportWidth();
boolean getScrollableTracksViewportHeight();