Почему при изменении размера на моем JScrollPanel изменяется мой объект (JPanel) внутри JPanel?

Question

Всякий раз, когда я изменить эту строку кода:

scrollPane.setSize(new Dimension(500, 500)); 

к

scrollPane.setSize(new Dimension(500, 600)); 

мой объект (JPanel) внутри моих JPanel изменений?

Путь видеть структуру будет:

 
Objects: JScrollPanel( JPanel   ( JPanel() ) ); 
names: scrollPanel ( tableCollection ( table1() ) ) 

import java.awt.Color; 
import java.awt.Dimension; 
import java.awt.Insets; 
import java.awt.Toolkit; 
import javax.swing.JPanel; 
import javax.swing.JScrollPane; 


public class testing extends javax.swing.JFrame { 

    public testing() { 
     initComponents(); 

     setMainFrameSize(); 
     addScrollPane(); 
     addTables(); 
    } 

    @SuppressWarnings("unchecked") 
    // <editor-fold defaultstate="collapsed" desc="Generated Code">       
    private void initComponents() { 

     setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE); 
     addComponentListener(new java.awt.event.ComponentAdapter() { 
      public void componentResized(java.awt.event.ComponentEvent evt) { 
       formComponentResized(evt); 
      } 
     }); 

     javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane()); 
     getContentPane().setLayout(layout); 
     layout.setHorizontalGroup(
      layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) 
      .addGap(0, 400, Short.MAX_VALUE) 
     ); 
     layout.setVerticalGroup(
      layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) 
      .addGap(0, 300, Short.MAX_VALUE) 
     ); 

     pack(); 
    }// </editor-fold>       

    private void formComponentResized(java.awt.event.ComponentEvent evt) {          
     setScrollPaneSize(); 
     setTableSize(); 
    }          

    public static void main(String args[]) { 
     //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) "> 
     /* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel. 
     * For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html 
     */ 
     try { 
      for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) { 
       if ("Nimbus".equals(info.getName())) { 
        javax.swing.UIManager.setLookAndFeel(info.getClassName()); 
        break; 
       } 
      } 
     } catch (ClassNotFoundException ex) { 
      java.util.logging.Logger.getLogger(testing.class.getName()).log(java.util.logging.Level.SEVERE, null, ex); 
     } catch (InstantiationException ex) { 
      java.util.logging.Logger.getLogger(testing.class.getName()).log(java.util.logging.Level.SEVERE, null, ex); 
     } catch (IllegalAccessException ex) { 
      java.util.logging.Logger.getLogger(testing.class.getName()).log(java.util.logging.Level.SEVERE, null, ex); 
     } catch (javax.swing.UnsupportedLookAndFeelException ex) { 
      java.util.logging.Logger.getLogger(testing.class.getName()).log(java.util.logging.Level.SEVERE, null, ex); 
     } 
     //</editor-fold> 
     java.awt.EventQueue.invokeLater(new Runnable() { 
      public void run() { 
       new testing().setVisible(true); 
      } 
     }); 
    } 

    JPanel tableCollection = new JPanel(); 
    JScrollPane scrollPane = new JScrollPane(tableCollection, JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED, 
              JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED); 

    // Variables declaration - do not modify      
    // End of variables declaration     

    void setMainFrameSize() { 
     this.setMinimumSize(new Dimension(800, 600)); 
     Dimension scnDimension = Toolkit.getDefaultToolkit().getScreenSize(); 
     Insets scnInsets = Toolkit.getDefaultToolkit().getScreenInsets(getGraphicsConfiguration()); 
     this.setSize(scnDimension.width, scnDimension.height-(scnInsets.bottom+scnInsets.top)); 
    } 

    void addScrollPane() { 
     scrollPane.setBackground(Color.red); 
     setScrollPaneSize(); 
     this.add(scrollPane); 

     addTableCollection(); 
    } 
    void setScrollPaneSize() { 
     scrollPane.setSize(new Dimension(500, 500)); 
     scrollPane.setLocation(0, barHeight); 
    } 

    void addTableCollection() { 
     tableCollection.setBackground(new Color(189, 195, 199)); 
     setTableCollectionSize(); 
    } 
    void setTableCollectionSize() { 
     tableCollection.setPreferredSize(new Dimension(550, 550)); 
    } 

    void addTables() { 
     table1.setBackground(new Color(52, 152, 219)); 

     tableCollection.add(table1); 

    } 
    void setTableSize() { 

     int tableHeight = tableCollection.getHeight()-tableHeightOffset*2; 
     table1.setSize(350, tableHeight); 
     table1.setLocation(0, 0); 
    } 

    int barHeight = 50; 
    int tableHeightOffset = 50; 
    int tableWidthOffset = 50; 
    int nTables = 5; 

    JPanel table1 = new JPanel(); 

} 

Answer 1

Просто пришлось добавить tableCollection.setLayout(null); так он может обрабатывать пользовательский SIZED JPanels внутри JPanel

Спасибо Йонаса JPanel inside another