螺纹“中的异常；主&x201D；java.awt.IllegalComponentStateException

2函数（位于javax.swing.JFrame.setContentPane（JFrame.java:698））

3函数（位于com.company.AuthorizationGUI.（AuthorizationGUI.java:21））

4函数（位于com.company.Client.connect（Client.java:42））

5函数（位于com.company.Client.（Client.java:21））

6函数（位于com.company.Client.getInstance（Client.java:30））

7函数（位于com.company.Client.main（Client.java:17））

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一个很好的解决方案。不要在Java中使用Swing库，它太旧了。更好的方法当然是JavaFX。

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尝试将问题缩小到仍然失败的最简单实现。您还应该指出代码失败的确切位置以及您试图修复的内容。'public void setContentPane（容器内容）{if（content==null）抛出新的非法组件状态异常（“contentPane不能设置为null”）；if（contentPane！=null&&contentPane.getParent（）==layeredPane）layeredPane.remove（contentPane）；contentPane=content；layeredPane.add（contentPane，JLayeredPane.FRAME_content_LAYER）；}'是的，不在评论中-编辑你的主要问题。@Alan我做了。

package javax.swing;

import java.applet.Applet;
import java.awt.*;
import java.awt.event.*;
import java.beans.*;
import java.security.AccessController;
import javax.accessibility.*;
import javax.swing.plaf.RootPaneUI;
import java.util.Vector;
import java.io.Serializable;
import javax.swing.border.*;
import sun.awt.AWTAccessor;
import sun.security.action.GetBooleanAction;


@SuppressWarnings("serial")
public class JRootPane extends JComponent implements Accessible {

    private static final String uiClassID = "RootPaneUI";


    public static final int COLOR_CHOOSER_DIALOG = 5;


    public static final int FILE_CHOOSER_DIALOG = 6;


    public static final int QUESTION_DIALOG = 7;


    public static final int WARNING_DIALOG = 8;

    private int windowDecorationStyle;


    protected JMenuBar menuBar;

    /** The content pane. */
    protected Container contentPane;

    /** The layered pane that manages the menu bar and content pane. */
    protected JLayeredPane layeredPane;

    protected Component glassPane;

    protected JButton defaultButton;

    boolean useTrueDoubleBuffering = true;

    static {
        LOG_DISABLE_TRUE_DOUBLE_BUFFERING =
            AccessController.doPrivileged(new GetBooleanAction(
                                   "swing.logDoubleBufferingDisable"));
        IGNORE_DISABLE_TRUE_DOUBLE_BUFFERING =
            AccessController.doPrivileged(new GetBooleanAction(
                                   "swing.ignoreDoubleBufferingDisable"));
    }


    public JRootPane() {
        setGlassPane(createGlassPane());
        setLayeredPane(createLayeredPane());
        setContentPane(createContentPane());
        setLayout(createRootLayout());
        setDoubleBuffered(true);
        updateUI();
    }


    public void setDoubleBuffered(boolean aFlag) {
        if (isDoubleBuffered() != aFlag) {
            super.setDoubleBuffered(aFlag);
            RepaintManager.currentManager(this).doubleBufferingChanged(this);
        }
    }


    public int getWindowDecorationStyle() {
        return windowDecorationStyle;
    }


    public void setWindowDecorationStyle(int windowDecorationStyle) {
        if (windowDecorationStyle < 0 ||
                  windowDecorationStyle > WARNING_DIALOG) {
            throw new IllegalArgumentException("Invalid decoration style");
        }
        int oldWindowDecorationStyle = getWindowDecorationStyle();
        this.windowDecorationStyle = windowDecorationStyle;
        firePropertyChange("windowDecorationStyle",
                            oldWindowDecorationStyle,
                            windowDecorationStyle);
    }


    public RootPaneUI getUI() {
        return (RootPaneUI)ui;
    }


    public void setUI(RootPaneUI ui) {
        super.setUI(ui);
    }



    public void updateUI() {
        setUI((RootPaneUI)UIManager.getUI(this));
    }



    public String getUIClassID() {
        return uiClassID;
    }


    protected JLayeredPane createLayeredPane() {
        JLayeredPane p = new JLayeredPane();
        p.setName(this.getName()+".layeredPane");
        return p;
    }


    protected Container createContentPane() {
        JComponent c = new JPanel();
        c.setName(this.getName()+".contentPane");
        c.setLayout(new BorderLayout() {

            public void addLayoutComponent(Component comp, Object constraints) {
                if (constraints == null) {
                    constraints = BorderLayout.CENTER;
                }
                super.addLayoutComponent(comp, constraints);
            }
        });
        return c;
    }


    protected Component createGlassPane() {
        JComponent c = new JPanel();
        c.setName(this.getName()+".glassPane");
        c.setVisible(false);
        ((JPanel)c).setOpaque(false);
        return c;
    }


    protected LayoutManager createRootLayout() {
        return new RootLayout();
    }


    public void setJMenuBar(JMenuBar menu) {
        if(menuBar != null && menuBar.getParent() == layeredPane)
            layeredPane.remove(menuBar);
        menuBar = menu;

        if(menuBar != null)
            layeredPane.add(menuBar, JLayeredPane.FRAME_CONTENT_LAYER);
    }


    @Deprecated
    public void setMenuBar(JMenuBar menu){
        if(menuBar != null && menuBar.getParent() == layeredPane)
            layeredPane.remove(menuBar);
        menuBar = menu;

        if(menuBar != null)
            layeredPane.add(menuBar, JLayeredPane.FRAME_CONTENT_LAYER);
    }


    public JMenuBar getJMenuBar() { return menuBar; }


    @Deprecated
    public JMenuBar getMenuBar() { return menuBar; }


    public void setContentPane(Container content) {
        if(content == null)
            throw new IllegalComponentStateException("contentPane cannot be set to null.");
        if(contentPane != null && contentPane.getParent() == layeredPane)
            layeredPane.remove(contentPane);
        contentPane = content;

        layeredPane.add(contentPane, JLayeredPane.FRAME_CONTENT_LAYER);
    }


    public Container getContentPane() { return contentPane; }


    public void setLayeredPane(JLayeredPane layered) {
        if(layered == null)
            throw new IllegalComponentStateException("layeredPane cannot be set to null.");
        if(layeredPane != null && layeredPane.getParent() == this)
            this.remove(layeredPane);
        layeredPane = layered;

        this.add(layeredPane, -1);
    }

    public JLayeredPane getLayeredPane() { return layeredPane; }


    public void setGlassPane(Component glass) {
        if (glass == null) {
            throw new NullPointerException("glassPane cannot be set to null.");
        }

        AWTAccessor.getComponentAccessor().setMixingCutoutShape(glass,
                new Rectangle());

        boolean visible = false;
        if (glassPane != null && glassPane.getParent() == this) {
            this.remove(glassPane);
            visible = glassPane.isVisible();
        }

        glass.setVisible(visible);
        glassPane = glass;
        this.add(glassPane, 0);
        if (visible) {
            repaint();
        }
    }


    public Component getGlassPane() {
        return glassPane;
    }


    @Override
    public boolean isValidateRoot() {
        return true;
    }


    public boolean isOptimizedDrawingEnabled() {
        return !glassPane.isVisible();
    }


    public void addNotify() {
        super.addNotify();
        enableEvents(AWTEvent.KEY_EVENT_MASK);
    }


    public void removeNotify() {
        super.removeNotify();
    }



    public void setDefaultButton(JButton defaultButton) {
        JButton oldDefault = this.defaultButton;

        if (oldDefault != defaultButton) {
            this.defaultButton = defaultButton;

            if (oldDefault != null) {
                oldDefault.repaint();
            }
            if (defaultButton != null) {
                defaultButton.repaint();
            }
        }

        firePropertyChange("defaultButton", oldDefault, defaultButton);
    }


    public JButton getDefaultButton() {
        return defaultButton;
    }

    final void setUseTrueDoubleBuffering(boolean useTrueDoubleBuffering) {
        this.useTrueDoubleBuffering = useTrueDoubleBuffering;
    }

    final boolean getUseTrueDoubleBuffering() {
        return useTrueDoubleBuffering;
    }

    final void disableTrueDoubleBuffering() {
        if (useTrueDoubleBuffering) {
            if (!IGNORE_DISABLE_TRUE_DOUBLE_BUFFERING) {
                if (LOG_DISABLE_TRUE_DOUBLE_BUFFERING) {
                    System.out.println("Disabling true double buffering for " +
                                       this);
                    Thread.dumpStack();
                }
                useTrueDoubleBuffering = false;
                RepaintManager.currentManager(this).
                        doubleBufferingChanged(this);
            }
        }
    }

    @SuppressWarnings("serial")
    static class DefaultAction extends AbstractAction {
        JButton owner;
        JRootPane root;
        boolean press;
        DefaultAction(JRootPane root, boolean press) {
            this.root = root;
            this.press = press;
        }
        public void setOwner(JButton owner) {
            this.owner = owner;
        }
        public void actionPerformed(ActionEvent e) {
            if (owner != null && SwingUtilities.getRootPane(owner) == root) {
                ButtonModel model = owner.getModel();
                if (press) {
                    model.setArmed(true);
                    model.setPressed(true);
                } else {
                    model.setPressed(false);
                }
            }
        }
        public boolean isEnabled() {
            return owner.getModel().isEnabled();
        }
    }



    protected void addImpl(Component comp, Object constraints, int index) {
        super.addImpl(comp, constraints, index);

        if(glassPane != null
            && glassPane.getParent() == this
            && getComponent(0) != glassPane) {
            add(glassPane, 0);
        }
    }



    @SuppressWarnings("serial")
    protected class RootLayout implements LayoutManager2, Serializable
    {

        public Dimension preferredLayoutSize(Container parent) {
            Dimension rd, mbd;
            Insets i = getInsets();

            if(contentPane != null) {
                rd = contentPane.getPreferredSize();
            } else {
                rd = parent.getSize();
            }
            if(menuBar != null && menuBar.isVisible()) {
                mbd = menuBar.getPreferredSize();
            } else {
                mbd = new Dimension(0, 0);
            }
            return new Dimension(Math.max(rd.width, mbd.width) + i.left + i.right,
                                        rd.height + mbd.height + i.top + i.bottom);
        }


        public Dimension minimumLayoutSize(Container parent) {
            Dimension rd, mbd;
            Insets i = getInsets();
            if(contentPane != null) {
                rd = contentPane.getMinimumSize();
            } else {
                rd = parent.getSize();
            }
            if(menuBar != null && menuBar.isVisible()) {
                mbd = menuBar.getMinimumSize();
            } else {
                mbd = new Dimension(0, 0);
            }
            return new Dimension(Math.max(rd.width, mbd.width) + i.left + i.right,
                        rd.height + mbd.height + i.top + i.bottom);
        }


        public Dimension maximumLayoutSize(Container target) {
            Dimension rd, mbd;
            Insets i = getInsets();
            if(menuBar != null && menuBar.isVisible()) {
                mbd = menuBar.getMaximumSize();
            } else {
                mbd = new Dimension(0, 0);
            }
            if(contentPane != null) {
                rd = contentPane.getMaximumSize();
            } else {
                // This is silly, but should stop an overflow error
                rd = new Dimension(Integer.MAX_VALUE,
                        Integer.MAX_VALUE - i.top - i.bottom - mbd.height - 1);
            }
            return new Dimension(Math.min(rd.width, mbd.width) + i.left + i.right,
                                         rd.height + mbd.height + i.top + i.bottom);
        }


        public void layoutContainer(Container parent) {
            Rectangle b = parent.getBounds();
            Insets i = getInsets();
            int contentY = 0;
            int w = b.width - i.right - i.left;
            int h = b.height - i.top - i.bottom;

            if(layeredPane != null) {
                layeredPane.setBounds(i.left, i.top, w, h);
            }
            if(glassPane != null) {
                glassPane.setBounds(i.left, i.top, w, h);
            }
            // Note: This is laying out the children in the layeredPane,
            // technically, these are not our children.
            if(menuBar != null && menuBar.isVisible()) {
                Dimension mbd = menuBar.getPreferredSize();
                menuBar.setBounds(0, 0, w, mbd.height);
                contentY += mbd.height;
            }
            if(contentPane != null) {
                contentPane.setBounds(0, contentY, w, h - contentY);
            }
        }

        public void addLayoutComponent(String name, Component comp) {}
        public void removeLayoutComponent(Component comp) {}
        public void addLayoutComponent(Component comp, Object constraints) {}
        public float getLayoutAlignmentX(Container target) { return 0.0f; }
        public float getLayoutAlignmentY(Container target) { return 0.0f; }
        public void invalidateLayout(Container target) {}
    }


    protected String paramString() {
        return super.paramString();
    }

/////////////////
// Accessibility support
////////////////


    public AccessibleContext getAccessibleContext() {
        if (accessibleContext == null) {
            accessibleContext = new AccessibleJRootPane();
        }
        return accessibleContext;
    }


    @SuppressWarnings("serial")
    protected class AccessibleJRootPane extends AccessibleJComponent {

        public AccessibleRole getAccessibleRole() {
            return AccessibleRole.ROOT_PANE;
        }


        public int getAccessibleChildrenCount() {
            return super.getAccessibleChildrenCount();
        }


        public Accessible getAccessibleChild(int i) {
            return super.getAccessibleChild(i);
        }
    } // inner class AccessibleJRootPane
}

public void setContentPane(Container content) {
        if(content == null)
            throw new IllegalComponentStateException("contentPane cannot be set to null.");
        if(contentPane != null && contentPane.getParent() == layeredPane)
            layeredPane.remove(contentPane);
        contentPane = content;

        layeredPane.add(contentPane, JLayeredPane.FRAME_CONTENT_LAYER);
    }

public void setContentPane(Container contentPane) {
        getRootPane().setContentPane(contentPane);
    }

 AuthorizationGUI() {
        setContentPane(contentPane);

        Dimension s = Toolkit.getDefaultToolkit().getScreenSize();
        int width = 300, height = 200;
        int X = (s.width - width) / 2;
        int Y = (s.height - height) / 2;
        setBounds(X, Y, width, height);

        errorInput.setVisible(false);
        enter.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                enter();
            }
        });
        registration.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                registration();
            }
        });

 private void connect() {
        try {
            clientSocket = new Socket("127.0.0.1", 1000);
            coos = new ObjectOutputStream(clientSocket.getOutputStream());
            cois = new ObjectInputStream(clientSocket.getInputStream());
            new AuthorizationGUI();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

private Client() {
        connect();
    }

public static Client getInstance() {
        Client localInstance = instance;
        if (localInstance == null) {
            synchronized (Client.class) {
                localInstance = instance;
                if (localInstance == null) {
                    instance = localInstance = new Client();
                }
            }
        }
        return localInstance;
    }

public static void main(String[] arg) {
        Client.getInstance();
    }