About JScrollPane in the JPanel layout change how do

I added a JTextArea JScrollPane but could not control him appear in the Panel position and size , setLocation and layout manager approach will not work, this how to do it ? ?
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paste the code first . .
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setPreferredSize (Dimension preferredSize) to set the preferred size of this component
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want to change the position you want to change the layout of the
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you should not set this layout manager , so Jframe default to use the default layout manager .
you
jSP.setLayout (null);
Set layout manager is empty,
set directly controls the position and size
JTextArea.setBounds (x, y, width, height);
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jSP.setLayout (null); set to null after the text box on the not coming. .  
how could I show here is normal ah , JSP, and taContent casually put the position and size ,

  class MyPanel extends JPanel{
  //    JTextArea taText = new JTextArea(8,2);
  
  
      JTextArea taContent = new JTextArea(12,59);
      
      JScrollPane  jSP = new JScrollPane(taContent);
      
      
      Font f = new Font("宋体", Font.BOLD, 20);
       
      public MyPanel(){
      	setLayout(null);
      	
          jSP.setBounds(5, 5, 600, 300);
          jSP.setOpaque(false);
          jSP.getViewport().setOpaque(false);
          jSP.setLocation(7, 7);
          this.add(jSP);
          //taContent.setLocation(100, 200);
          taContent.setLineWrap(true);
          taContent.setOpaque(false);
          taContent.setBackground(Color.blue);
          taContent.setFont(f);
          taContent.setSize(200,200);
          jSP.setLayout(null);
          taContent.setBounds(300,200, 100, 100);
          jSP.add(taContent);
          
      }
  }

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this is part of the JPanel

  public class MyPanel extends JPanel{
  	JTextArea taText = new JTextArea(8,2);
  	JTextArea taContent = new JTextArea(12,59);
  	JScrollPane  jSP = new JScrollPane(taContent);
  	Font f = new Font("宋体", Font.BOLD, 20);
  	
  	public MyPanel(){
  		jSP.setSize(600, 600);
  		jSP.setOpaque(false);
  		jSP.getViewport().setOpaque(false);
  		jSP.setLocation(7, 7);
  		this.add(jSP);
  		//taContent.setLocation(100, 200);
  		taContent.setLineWrap(true);
  		taContent.setOpaque(false);
  		taContent.setBackground(Color.blue);
  		taContent.setFont(f);
  		taContent.setSize(200,200);
  	}
  

This is part of the JFrame

  public class MyFrame extends JFrame{
  	
  	JButton jbEnter = new JButton("发送"); 
  	
  	public MyFrame(String name){
  		super(name);
  	//	this.setContentPane(new MyPanel());
  		this.add(new MyPanel());
  		this.setSize(800,450);
  		this.setResizable(false);
  		
  		this.setDefaultCloseOperation(3);
  		this.setVisible(true);
  	}
  }
  

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just tried, indeed can change the size, but can not change the position of ah.
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jSP.setPreferredSize(new Dimension(800,450));

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Well, probably should be a kind of how to change the law? ?
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jSP.setLayout (null); set to null after the text box to get out . .
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jSP.setLayout (null); set to null after the text box to get out . .          
how could I show here is normal ah , JSP, and taContent casually put the position and size ,   
  

  class MyPanel extends JPanel{
  //    JTextArea taText = new JTextArea(8,2);
  
  
      JTextArea taContent = new JTextArea(12,59);
      
      JScrollPane  jSP = new JScrollPane(taContent);
      
      
      Font f = new Font("宋体", Font.BOLD, 20);
       
      public MyPanel(){
      	setLayout(null);
      	
          jSP.setBounds(5, 5, 600, 300);
          jSP.setOpaque(false);
          jSP.getViewport().setOpaque(false);
          jSP.setLocation(7, 7);
          this.add(jSP);
          //taContent.setLocation(100, 200);
          taContent.setLineWrap(true);
          taContent.setOpaque(false);
          taContent.setBackground(Color.blue);
          taContent.setFont(f);
          taContent.setSize(200,200);
          jSP.setLayout(null);
          taContent.setBounds(300,200, 100, 100);
          jSP.add(taContent);
          
      }
  }

  TU generally ok, thank you , thank you, there is a small problem is not resolved, I look back . .