javax.swing: public class: JPanel

javax.swing
public class: JPanel [javadoc | source]

java.lang.Object
   java.awt.Component
      java.awt.Container
         javax.swing.JComponent
            javax.swing.JPanel

All Implemented Interfaces:
Accessible, HasGetTransferHandler, Serializable, MenuContainer, ImageObserver

Direct Known Subclasses:
SidePane, JPanelNeuerKunde, VCirPanel, SwatchPanel, XPanel, ScrollLabel, DefaultEditor, JPanelEtatEinsehen, DefaultPreviewPanel, CMapDisplay, JChecklistInfo, SidePaneHeader, VEllPanel, JTextFields, DefaultSwatchChooserPanel, BeanEditPanel, TaskBar, VShapePanel, ScrollableTabPanel, JPanelKundenUebersicht, SETIPanel, ListTablePanel, GlyphPanel, JPanelNeuerLieferant, MainSwatchPanel, FieldPanel, AbstractColorChooserPanel, SwatchChooserPanel, PhoneMachinePanel, BoxToolbar, RecentSwatchPanel, TabContainer, ListEditor, VDiamPanel, JPanelArbeitsplatzlager, PlaylistEditor, VTrgPanel, DollarsPanel, Beale, JPanelKundeBearbeiten, SwatchPanel, KDollarsPanel, EditableFigureComponent, SidePaneComponent, TablePanel, GroupSelector, MainSwatchPanel, JPanelZahlungseingang, DisplayFigureComponent, JPanelLieferantBearbeiten, JPanelHilfe, DefaultRGBChooserPanel, JAIFilePreviewer, CroppedEdge, VOctPanel, ThreadManagerPanel, AbstractOverviewPanel, DisplayPanel, RecentSwatchPanel, PrefsPane, JPanelLieferantenliste, JPanelVertragEinsehen, JPanelNeuerVertrag, DefaultHSBChooserPanel, NumberEditor, Dict, SpoolViewerPanel, VRectPanel, GPSInfoPanel, JPanelSimulationStart, CWlanLayer, MsgWriter, DateEditor, DetailPanel, CMapLayer, ColorIndicator, JPanelOptions, EncodingChooser, DictDockable, MsgViewer

JPanel is a generic lightweight container. For examples and task-oriented documentation for JPanel, see How to Use Panels, a section in The Java Tutorial.

Warning: Swing is not thread safe. For more information see Swing's Threading Policy.

Warning: Serialized objects of this class will not be compatible with future Swing releases. The current serialization support is appropriate for short term storage or RMI between applications running the same version of Swing. As of 1.4, support for long term storage of all JavaBeans^TM has been added to the java.beans package. Please see java.beans.XMLEncoder .

beaninfo: description - : A generic lightweight container.

author: Arnaud - Weber

author: Steve - Wilson

Nested Class Summary:
protected class	JPanel.AccessibleJPanel	This class implements accessibility support for the `JPanel` class. It provides an implementation of the Java Accessibility API appropriate to panel user-interface elements. Warning: Serialized objects of this class will not be compatible with future Swing releases. The current serialization support is appropriate for short term storage or RMI between applications running the same version of Swing. As of 1.4, support for long term storage of all JavaBeans^TM has been added to the `java.beans` package. Please see {@link java.beans.XMLEncoder}.

Fields inherited from javax.swing.JComponent:
DEBUG_GRAPHICS_LOADED, ui, listenerList, paintingChild, WHEN_FOCUSED, WHEN_ANCESTOR_OF_FOCUSED_COMPONENT, WHEN_IN_FOCUSED_WINDOW, UNDEFINED_CONDITION, TOOL_TIP_TEXT_KEY, focusController, accessibleContext

Fields inherited from java.awt.Container:
ncomponents, component, layoutMgr, containerListener, listeningChildren, listeningBoundsChildren, descendantsCount, INCLUDE_SELF, SEARCH_HEAVYWEIGHTS, modalComp, modalAppContext

Fields inherited from java.awt.Component:
TOP_ALIGNMENT, CENTER_ALIGNMENT, BOTTOM_ALIGNMENT, RIGHT_ALIGNMENT, LEFT_ALIGNMENT, treeLock, x, y, width, height, foreground, background, font, peerFont, cursor, locale, ignoreRepaint, visible, enabled, valid, dropTarget, popups, name, nameExplicitlySet, focusable, isFocusTraversableOverridden, focusTraversalKeys, focusTraversalKeysEnabled, minSize, prefSize, newEventsOnly, eventMask, changeSupport, isPacked, componentSerializedDataVersion, accessibleContext, componentListener, focusListener, keyListener, mouseListener, mouseMotionListener, mouseWheelListener, inputMethodListener, hierarchyListener, hierarchyBoundsListener, parent, peer, orientation, graphicsConfig, bufferStrategy

Fields inherited from java.awt.Component:

TOP_ALIGNMENT, CENTER_ALIGNMENT, BOTTOM_ALIGNMENT, RIGHT_ALIGNMENT, LEFT_ALIGNMENT, treeLock, x, y, width, height, foreground, background, font, peerFont, cursor, locale, ignoreRepaint, visible, enabled, valid, dropTarget, popups, name, nameExplicitlySet, focusable, isFocusTraversableOverridden, focusTraversalKeys, focusTraversalKeysEnabled, minSize, prefSize, newEventsOnly, eventMask, changeSupport, isPacked, componentSerializedDataVersion, accessibleContext, componentListener, focusListener, keyListener, mouseListener, mouseMotionListener, mouseWheelListener, inputMethodListener, hierarchyListener, hierarchyBoundsListener, parent, peer, orientation, graphicsConfig, bufferStrategy

Constructor:

Constructor:
public JPanel() { this(true); } Creates a new `JPanel` with a double buffer and a flow layout.
public JPanel(LayoutManager layout) { this(layout, true); } Create a new buffered JPanel with the specified layout manager Parameters: `layout` - the LayoutManager to use
public JPanel(boolean isDoubleBuffered) { this(new FlowLayout(), isDoubleBuffered); } Creates a new `JPanel` with `FlowLayout` and the specified buffering strategy. If `isDoubleBuffered` is true, the `JPanel` will use a double buffer. Parameters: `isDoubleBuffered` - a boolean, true for double-buffering, which uses additional memory space to achieve fast, flicker-free updates
public JPanel(LayoutManager layout, boolean isDoubleBuffered) { setLayout(layout); setDoubleBuffered(isDoubleBuffered); setUIProperty("opaque", Boolean.TRUE); updateUI(); } Creates a new JPanel with the specified layout manager and buffering strategy. Parameters: `layout` - the LayoutManager to use `isDoubleBuffered` - a boolean, true for double-buffering, which uses additional memory space to achieve fast, flicker-free updates

 public JPanel() {
        this(true);
}

Creates a new JPanel with a double buffer and a flow layout.

 public JPanel(LayoutManager layout) {
        this(layout, true);
}

Create a new buffered JPanel with the specified layout manager

Parameters:

layout - the LayoutManager to use

 public JPanel(boolean isDoubleBuffered) {
        this(new FlowLayout(), isDoubleBuffered);
}

Creates a new JPanel with FlowLayout and the specified buffering strategy. If isDoubleBuffered is true, the JPanel will use a double buffer.

Parameters:

isDoubleBuffered - a boolean, true for double-buffering, which uses additional memory space to achieve fast, flicker-free updates

 public JPanel(LayoutManager layout,
    boolean isDoubleBuffered) {
                                                            
        setLayout(layout);
        setDoubleBuffered(isDoubleBuffered);
        setUIProperty("opaque", Boolean.TRUE);
        updateUI();
}

Creates a new JPanel with the specified layout manager and buffering strategy.

Parameters:

layout - the LayoutManager to use

isDoubleBuffered - a boolean, true for double-buffering, which uses additional memory space to achieve fast, flicker-free updates

Method from javax.swing.JPanel Summary:
getAccessibleContext, getUI, getUIClassID, paramString, setUI, updateUI

Methods from javax.swing.JComponent:
_paintImmediately, addAncestorListener, addNotify, addVetoableChangeListener, alwaysOnTop, checkIfChildObscuredBySibling, clientPropertyChanged, compWriteObjectNotify, componentInputMapChanged, computeVisibleRect, computeVisibleRect, contains, createToolTip, disable, dndDone, dropLocationForPoint, enable, firePropertyChange, firePropertyChange, firePropertyChange, fireVetoableChange, getAccessibleContext, getActionForKeyStroke, getActionMap, getActionMap, getAlignmentX, getAlignmentY, getAncestorListeners, getAutoscrolls, getBaseline, getBaselineResizeBehavior, getBorder, getBounds, getClientProperty, getComponentGraphics, getComponentPopupMenu, getConditionForKeyStroke, getCreatedDoubleBuffer, getDebugGraphicsOptions, getDefaultLocale, getFontMetrics, getGraphics, getGraphicsInvoked, getHeight, getInheritsPopupMenu, getInputMap, getInputMap, getInputMap, getInputVerifier, getInsets, getInsets, getListeners, getLocation, getManagingFocusBackwardTraversalKeys, getManagingFocusForwardTraversalKeys, getMaximumSize, getMinimumSize, getNextFocusableComponent, getPopupLocation, getPreferredSize, getRegisteredKeyStrokes, getRootPane, getSize, getToolTipLocation, getToolTipText, getToolTipText, getTopLevelAncestor, getTransferHandler, getUIClassID, getVerifyInputWhenFocusTarget, getVetoableChangeListeners, getVisibleRect, getWidth, getWriteObjCounter, getX, getY, grabFocus, isDoubleBuffered, isLightweightComponent, isManagingFocus, isOpaque, isOptimizedDrawingEnabled, isPainting, isPaintingForPrint, isPaintingOrigin, isPaintingTile, isRequestFocusEnabled, isValidateRoot, paint, paintBorder, paintChildren, paintComponent, paintForceDoubleBuffered, paintImmediately, paintImmediately, paintToOffscreen, paramString, print, printAll, printBorder, printChildren, printComponent, processComponentKeyEvent, processKeyBinding, processKeyBindings, processKeyBindingsForAllComponents, processKeyEvent, processMouseEvent, processMouseMotionEvent, putClientProperty, rectangleIsObscured, registerKeyboardAction, registerKeyboardAction, removeAncestorListener, removeNotify, removeVetoableChangeListener, repaint, repaint, requestDefaultFocus, requestFocus, requestFocus, requestFocusInWindow, requestFocusInWindow, resetKeyboardActions, reshape, revalidate, safelyGetGraphics, safelyGetGraphics, scrollRectToVisible, setActionMap, setAlignmentX, setAlignmentY, setAutoscrolls, setBackground, setBorder, setComponentPopupMenu, setCreatedDoubleBuffer, setDebugGraphicsOptions, setDefaultLocale, setDoubleBuffered, setDropLocation, setEnabled, setFocusTraversalKeys, setFont, setForeground, setInheritsPopupMenu, setInputMap, setInputVerifier, setMaximumSize, setMinimumSize, setNextFocusableComponent, setOpaque, setPaintingChild, setPreferredSize, setRequestFocusEnabled, setToolTipText, setTransferHandler, setUI, setUIProperty, setVerifyInputWhenFocusTarget, setVisible, setWriteObjCounter, shouldDebugGraphics, superProcessMouseMotionEvent, unregisterKeyboardAction, update, updateUI

Methods from javax.swing.JComponent:

_paintImmediately, addAncestorListener, addNotify, addVetoableChangeListener, alwaysOnTop, checkIfChildObscuredBySibling, clientPropertyChanged, compWriteObjectNotify, componentInputMapChanged, computeVisibleRect, computeVisibleRect, contains, createToolTip, disable, dndDone, dropLocationForPoint, enable, firePropertyChange, firePropertyChange, firePropertyChange, fireVetoableChange, getAccessibleContext, getActionForKeyStroke, getActionMap, getActionMap, getAlignmentX, getAlignmentY, getAncestorListeners, getAutoscrolls, getBaseline, getBaselineResizeBehavior, getBorder, getBounds, getClientProperty, getComponentGraphics, getComponentPopupMenu, getConditionForKeyStroke, getCreatedDoubleBuffer, getDebugGraphicsOptions, getDefaultLocale, getFontMetrics, getGraphics, getGraphicsInvoked, getHeight, getInheritsPopupMenu, getInputMap, getInputMap, getInputMap, getInputVerifier, getInsets, getInsets, getListeners, getLocation, getManagingFocusBackwardTraversalKeys, getManagingFocusForwardTraversalKeys, getMaximumSize, getMinimumSize, getNextFocusableComponent, getPopupLocation, getPreferredSize, getRegisteredKeyStrokes, getRootPane, getSize, getToolTipLocation, getToolTipText, getToolTipText, getTopLevelAncestor, getTransferHandler, getUIClassID, getVerifyInputWhenFocusTarget, getVetoableChangeListeners, getVisibleRect, getWidth, getWriteObjCounter, getX, getY, grabFocus, isDoubleBuffered, isLightweightComponent, isManagingFocus, isOpaque, isOptimizedDrawingEnabled, isPainting, isPaintingForPrint, isPaintingOrigin, isPaintingTile, isRequestFocusEnabled, isValidateRoot, paint, paintBorder, paintChildren, paintComponent, paintForceDoubleBuffered, paintImmediately, paintImmediately, paintToOffscreen, paramString, print, printAll, printBorder, printChildren, printComponent, processComponentKeyEvent, processKeyBinding, processKeyBindings, processKeyBindingsForAllComponents, processKeyEvent, processMouseEvent, processMouseMotionEvent, putClientProperty, rectangleIsObscured, registerKeyboardAction, registerKeyboardAction, removeAncestorListener, removeNotify, removeVetoableChangeListener, repaint, repaint, requestDefaultFocus, requestFocus, requestFocus, requestFocusInWindow, requestFocusInWindow, resetKeyboardActions, reshape, revalidate, safelyGetGraphics, safelyGetGraphics, scrollRectToVisible, setActionMap, setAlignmentX, setAlignmentY, setAutoscrolls, setBackground, setBorder, setComponentPopupMenu, setCreatedDoubleBuffer, setDebugGraphicsOptions, setDefaultLocale, setDoubleBuffered, setDropLocation, setEnabled, setFocusTraversalKeys, setFont, setForeground, setInheritsPopupMenu, setInputMap, setInputVerifier, setMaximumSize, setMinimumSize, setNextFocusableComponent, setOpaque, setPaintingChild, setPreferredSize, setRequestFocusEnabled, setToolTipText, setTransferHandler, setUI, setUIProperty, setVerifyInputWhenFocusTarget, setVisible, setWriteObjCounter, shouldDebugGraphics, superProcessMouseMotionEvent, unregisterKeyboardAction, update, updateUI

Methods from java.awt.Container:
add, add, add, add, add, addContainerListener, addImpl, addNotify, addPropertyChangeListener, addPropertyChangeListener, adjustDecendantsOnParent, adjustDescendants, adjustListeningChildren, applyComponentOrientation, areFocusTraversalKeysSet, canContainFocusOwner, checkGD, clearCurrentFocusCycleRootOnHide, clearMostRecentFocusOwnerOnHide, containsFocus, countComponents, countHierarchyMembers, createChildHierarchyEvents, createHierarchyEvents, decreaseComponentCount, deliverEvent, dispatchEventImpl, dispatchEventToSelf, doLayout, eventEnabled, findComponentAt, findComponentAt, findComponentAt, findComponentAtImpl, getAccessibleAt, getAccessibleChild, getAccessibleChildrenCount, getAlignmentX, getAlignmentY, getComponent, getComponentAt, getComponentAt, getComponentCount, getComponentZOrder, getComponents, getComponents_NoClientCode, getContainerListeners, getDropTargetEventTarget, getFocusTraversalKeys, getFocusTraversalPolicy, getHeavyweightContainer, getInsets, getLayout, getListeners, getMaximumSize, getMinimumSize, getMouseEventTarget, getMousePosition, getPreferredSize, getTraversalRoot, increaseComponentCount, initializeFocusTraversalKeys, insets, invalidate, invalidateTree, isAncestorOf, isFocusCycleRoot, isFocusCycleRoot, isFocusTraversalPolicyProvider, isFocusTraversalPolicySet, isSameOrAncestorOf, layout, lightweightPaint, lightweightPrint, list, list, locate, minimumSize, mixOnHiding, mixOnReshaping, mixOnShowing, mixOnZOrderChanging, numListening, paint, paintComponents, paintHeavyweightComponents, paramString, postProcessKeyEvent, postsOldMouseEvents, preProcessKeyEvent, preferredSize, print, printComponents, printHeavyweightComponents, processContainerEvent, processEvent, proxyEnableEvents, recursiveApplyCurrentShape, recursiveApplyCurrentShape, recursiveApplyCurrentShape, recursiveSubtractAndApplyShape, recursiveSubtractAndApplyShape, recursiveSubtractAndApplyShape, remove, remove, removeAll, removeContainerListener, removeNotify, setComponentZOrder, setFocusCycleRoot, setFocusTraversalKeys, setFocusTraversalPolicy, setFocusTraversalPolicyProvider, setFont, setLayout, transferFocusDownCycle, update, validate, validateTree

Methods from java.awt.Container:

add, add, add, add, add, addContainerListener, addImpl, addNotify, addPropertyChangeListener, addPropertyChangeListener, adjustDecendantsOnParent, adjustDescendants, adjustListeningChildren, applyComponentOrientation, areFocusTraversalKeysSet, canContainFocusOwner, checkGD, clearCurrentFocusCycleRootOnHide, clearMostRecentFocusOwnerOnHide, containsFocus, countComponents, countHierarchyMembers, createChildHierarchyEvents, createHierarchyEvents, decreaseComponentCount, deliverEvent, dispatchEventImpl, dispatchEventToSelf, doLayout, eventEnabled, findComponentAt, findComponentAt, findComponentAt, findComponentAtImpl, getAccessibleAt, getAccessibleChild, getAccessibleChildrenCount, getAlignmentX, getAlignmentY, getComponent, getComponentAt, getComponentAt, getComponentCount, getComponentZOrder, getComponents, getComponents_NoClientCode, getContainerListeners, getDropTargetEventTarget, getFocusTraversalKeys, getFocusTraversalPolicy, getHeavyweightContainer, getInsets, getLayout, getListeners, getMaximumSize, getMinimumSize, getMouseEventTarget, getMousePosition, getPreferredSize, getTraversalRoot, increaseComponentCount, initializeFocusTraversalKeys, insets, invalidate, invalidateTree, isAncestorOf, isFocusCycleRoot, isFocusCycleRoot, isFocusTraversalPolicyProvider, isFocusTraversalPolicySet, isSameOrAncestorOf, layout, lightweightPaint, lightweightPrint, list, list, locate, minimumSize, mixOnHiding, mixOnReshaping, mixOnShowing, mixOnZOrderChanging, numListening, paint, paintComponents, paintHeavyweightComponents, paramString, postProcessKeyEvent, postsOldMouseEvents, preProcessKeyEvent, preferredSize, print, printComponents, printHeavyweightComponents, processContainerEvent, processEvent, proxyEnableEvents, recursiveApplyCurrentShape, recursiveApplyCurrentShape, recursiveApplyCurrentShape, recursiveSubtractAndApplyShape, recursiveSubtractAndApplyShape, recursiveSubtractAndApplyShape, remove, remove, removeAll, removeContainerListener, removeNotify, setComponentZOrder, setFocusCycleRoot, setFocusTraversalKeys, setFocusTraversalPolicy, setFocusTraversalPolicyProvider, setFont, setLayout, transferFocusDownCycle, update, validate, validateTree

Methods from java.awt.Component:
action, add, addComponentListener, addFocusListener, addHierarchyBoundsListener, addHierarchyListener, addInputMethodListener, addKeyListener, addMouseListener, addMouseMotionListener, addMouseWheelListener, addNotify, addPropertyChangeListener, addPropertyChangeListener, applyComponentOrientation, areFocusTraversalKeysSet, bounds, checkImage, checkImage, coalesceEvents, contains, contains, createImage, createImage, createVolatileImage, createVolatileImage, deliverEvent, disable, disableEvents, dispatchEvent, dispatchEventImpl, doLayout, enable, enable, enableEvents, enableInputMethods, eventTypeEnabled, findNextFocusComponent, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, generateName, getAccessibleContext, getAlignmentX, getAlignmentY, getBackground, getBounds, getBounds, getColorModel, getComponentAt, getComponentAt, getComponentListeners, getComponentOrientation, getCursor, getDropTarget, getFocusCycleRootAncestor, getFocusListeners, getFocusTraversalKeys, getFocusTraversalKeysEnabled, getFont, getFontMetrics, getForeground, getGraphics, getGraphicsConfiguration, getGraphicsConfigurationImpl, getHeight, getHierarchyBoundsListeners, getHierarchyListeners, getIgnoreRepaint, getInputContext, getInputMethodListeners, getInputMethodRequests, getKeyListeners, getListeners, getLocale, getLocation, getLocation, getLocationOnScreen, getMaximumSize, getMinimumSize, getMouseListeners, getMouseMotionListeners, getMouseWheelListeners, getName, getParent, getPeer, getPreferredSize, getPropertyChangeListeners, getPropertyChangeListeners, getSize, getSize, getToolkit, getTreeLock, getWidth, getX, getY, gotFocus, handleEvent, hasFocus, hide, imageUpdate, inside, invalidate, isBackgroundSet, isCursorSet, isDisplayable, isDoubleBuffered, isEnabled, isFocusCycleRoot, isFocusOwner, isFocusTraversable, isFocusable, isFontSet, isForegroundSet, isLightweight, isOpaque, isShowing, isValid, isVisible, keyDown, keyUp, layout, list, list, list, list, list, locate, location, lostFocus, minimumSize, mouseDown, mouseDrag, mouseEnter, mouseExit, mouseMove, mouseUp, move, nextFocus, paint, paintAll, paramString, postEvent, preferredSize, prepareImage, prepareImage, print, printAll, processComponentEvent, processEvent, processFocusEvent, processHierarchyBoundsEvent, processHierarchyEvent, processInputMethodEvent, processKeyEvent, processMouseEvent, processMouseMotionEvent, processMouseWheelEvent, remove, removeComponentListener, removeFocusListener, removeHierarchyBoundsListener, removeHierarchyListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, removeMouseWheelListener, removeNotify, removePropertyChangeListener, removePropertyChangeListener, repaint, repaint, repaint, repaint, requestFocus, requestFocus, requestFocusInWindow, requestFocusInWindow, reshape, resize, resize, setBackground, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setEnabled, setFocusTraversalKeys, setFocusTraversalKeysEnabled, setFocusable, setFont, setForeground, setIgnoreRepaint, setLocale, setLocation, setLocation, setName, setPeer, setSize, setSize, setVisible, show, show, size, toString, transferFocus, transferFocusBackward, transferFocusUpCycle, translateEvent, update, validate

Methods from java.awt.Component:

Methods from java.lang.Object:
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method from javax.swing.JPanel Detail:
public AccessibleContext getAccessibleContext() { if (accessibleContext == null) { accessibleContext = new AccessibleJPanel(); } return accessibleContext; } Gets the AccessibleContext associated with this JPanel. For JPanels, the AccessibleContext takes the form of an AccessibleJPanel. A new AccessibleJPanel instance is created if necessary.
public PanelUI getUI() { return (PanelUI)ui; } Returns the look and feel (L&F) object that renders this component.
public String getUIClassID() { return uiClassID; } Returns a string that specifies the name of the L&F class that renders this component.
protected String paramString() { return super.paramString(); } Returns a string representation of this JPanel. This method is intended to be used only for debugging purposes, and the content and format of the returned string may vary between implementations. The returned string may be empty but may not be `null`.
public void setUI(PanelUI ui) { super.setUI(ui); } Sets the look and feel (L&F) object that renders this component.
public void updateUI() { setUI((PanelUI)UIManager.getUI(this)); } Resets the UI property with a value from the current look and feel.

Method from javax.swing.JPanel Detail:

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

Gets the AccessibleContext associated with this JPanel. For JPanels, the AccessibleContext takes the form of an AccessibleJPanel. A new AccessibleJPanel instance is created if necessary.

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

Returns the look and feel (L&F) object that renders this component.

 public String getUIClassID() {
        return uiClassID;
}

Returns a string that specifies the name of the L&F class that renders this component.

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

null

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

Sets the look and feel (L&F) object that renders this component.

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

Resets the UI property with a value from the current look and feel.