How to a add a vertical scroll bar to a JTextArea in Swing?

You use a JScrollpane.

... and add the JTextArea to the scrollpane constructor, smthg like :

JScrollPane(Component view)
Creates a JScrollPane that displays the contents of the specified component, where both horizontal and vertical scrollbars appear whenever the component's contents are larger than the view.

@krakatoa I am sorry but I don't understand your advice. Have you looked at all at my code? I added

protected JScrollPane scrollPane1;
protected JScrollPane scrollPane2;

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then I added text areas to them

scrollPane1 = new JScrollPane(textArea1);
scrollPane2 = new JScrollPane(textArea2);

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and finally I added both JScrollPane to jframe

//this.add(this.textArea1);
this.add(scrollPane1);
//this.add(this.textArea2);
this.add(scrollPane2);

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But it doesn't work.

It probably didnt work because you didnt enter sufficient text to make the bars appear.

But if you did, then you've done something wrong, in which case follow this rough stuff :

import java.util.*;
import javax.swing.*;
import java.awt.*;

class Scr extends JFrame{

public static void main(String[] args){


Scr scr = new Scr();

scr.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);

scr.setSize(new Dimension(200,300));

JScrollPane jscrp = new JScrollPane(new JTextArea());

scr.add(jscrp);

scr.setVisible(true);

}




}

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(and no, I didnt look at your code, because that has no impact on how the principle here works).

Failing that, if you mean you want the bars there ALL THE TIME, then you have to set the policy for that.

I've been using scrollbars in the past, and I know about

JScrollPane.VERTICAL_SCROLLBAR_ALWAYS, JScrollPane.HORIZONTAL_SCROLLBAR_NEVER

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etc.
but there is something very wrong in this particular case: it's not that I haven't entered enough of text it's that THERE IS NO JTEXTAREA (altogether with JScrollPane) at all.

THERE IS NO JTEXTAREA

How are we supposed to know that? You haven't posted the code where the JTA is created - so  we cannot know. It's up to you to create the JTA - you can see clearly in my code that a JTA is created, and that the desired effect is achieved. Look at your code again. Or post it.

I have posted my code! Look at the first post again.
it's that there is no JTA in the final result:

Right, so if you knew there was no JTextArea, why was your question asking about the lack of a vertical scrollbar?

What is your problem? What do you don't understand?
JTextArea is added to JScrollPane and JScrollPane is added to JFrame but as a final result neither JTextArea or JScrollPane are displayed.

OK so afaics, it's your layout manager that is causing the problem. Get rid of it.

You'll have to do some cleaning up (resizing etc), but this cut-down of your code works for me, (once you resize the frame manually, and then enter text to cause the scrollbars to kick in) :

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;

public class GUI extends JPanel {

	
	protected JTextArea textArea1;
	protected JTextArea textArea2;
	protected JScrollPane scrollPane1;
	protected JScrollPane scrollPane2;
	private JLabel label1;
	private JLabel label2;
	private JButton jbutton1;
	private JButton jbutton2;
	private JButton jbutton3;

	public static void main(String[] args) {
		
		final JFrame frame = new JFrame("S1 Log Decryptor v1.0");
		frame.setDefaultCloseOperation(3);
		frame.add(new GUI());
		frame.setSize(800, 600);
		frame.setVisible(true);
	}

	public GUI() {
		//setLayout(null);

		(label1 = new JLabel()).setText("Enter encrypted string:");
		(label2 = new JLabel()).setText("Decryption result:");
		(jbutton1 = new JButton()).setText("Process");
		(jbutton2 = new JButton()).setText("Clear input");
		(jbutton3 = new JButton()).setText("About");

		(textArea1 = new JTextArea(10, 80)).setEditable(true);
		textArea1.setLineWrap(true);
		label1.setBounds(10, 10, 250, 25);
		textArea1.setBounds(10, 40, 765, 200);

		(textArea2 = new JTextArea(10, 80)).setEditable(false);
		textArea2.setLineWrap(true);
		label2.setBounds(10, 320, 200, 25);
		textArea2.setBounds(10, 350, 765, 200);

		jbutton1.setBounds(10, 270, 150, 25);
		jbutton2.setBounds(200, 270, 150, 25);
		jbutton3.setBounds(625, 270, 150, 25);

		scrollPane1 = new JScrollPane(textArea1);
		scrollPane2 = new JScrollPane(textArea2);

		this.add(label1);
		this.add(jbutton1);
		this.add(jbutton2);
		this.add(jbutton3);
		this.add(label2);
		//this.add(this.textArea1);
		this.add(scrollPane1);
		//this.add(this.textArea2);
		this.add(scrollPane2);
	}
	
	}

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