AWT Component类 - AWT
介绍
Component 类 是一个非菜单用户界面控件，是AWT一个抽象基类。组件表示图形表示的对象。
类的声明
以下是声明的java.awt.Component类：
public abstract class Component
extends Object
implements ImageObserver, MenuContainer, Serializable
字段域
以下是 java.awt.Component 类的字段:
static float BOTTOM_ALIGNMENT -- 易于使用的常数getAlignmentY.
static float CENTER_ALIGNMENT -- 易于使用的常数 getAlignmentY 和 getAlignmentX。
static float LEFT_ALIGNMENT -- 易于使用常数getAlignmentX。
static float RIGHT_ALIGNMENT -- 易于使用常数getAlignmentX。
static float TOP_ALIGNMENT -- 易于使用的常数 getAlignmentY().
类的构造函数
| S.N. | 构造函数与说明 |
|---|---|
| 1 | protected Component() 这将创建一个新的组件。 |
类方法
| S.N. | 方法和说明 |
|---|---|
| 1 | boolean action(Event evt, Object what) Deprecated. As of JDK version 1.1, should register this component as ActionListener on component which fires action events. |
| 2 | void add(PopupMenu popup) Adds the specified popup menu to the component. |
| 3 | void addComponentListener(ComponentListener l) Adds the specified component listener to receive component events from this component. |
| 4 | void addFocusListener(FocusListener l) Adds the specified focus listener to receive focus events from this component when this component gains input focus. |
| 5 | void addHierarchyBoundsListener(HierarchyBoundsListener l) Adds the specified hierarchy bounds listener to receive hierarchy bounds events from this component when the hierarchy to which this container belongs changes. |
| 6 | void addHierarchyListener(HierarchyListener l) Adds the specified hierarchy listener to receive hierarchy changed events from this component when the hierarchy to which this container belongs changes. |
| 7 | void addInputMethodListener(InputMethodListener l) Adds the specified input method listener to receive input method events from this component. |
| 8 | void addKeyListener(KeyListener l) Adds the specified key listener to receive key events from this component. |
| 9 | void addMouseListener(MouseListener l) Adds the specified mouse listener to receive mouse events from this component. |
| 10 | void addMouseMotionListener(MouseMotionListener l) Adds the specified mouse motion listener to receive mouse motion events from this component. |
| 11 | void addMouseWheelListener(MouseWheelListener l) Adds the specified mouse wheel listener to receive mouse wheel events from this component. |
| 12 | void addNotify() Makes this Component displayable by connecting it to a native screen resource. |
| 13 | void addPropertyChangeListener(PropertyChangeListener listener) Adds a PropertyChangeListener to the listener list. |
| 14 | void addPropertyChangeListener(String propertyName, PropertyChangeListener listener) Adds a PropertyChangeListener to the listener list for a specific property. |
| 15 | void applyComponentOrientation(ComponentOrientation orientation) Sets the ComponentOrientation property of this component and all components contained within it. |
| 16 | boolean areFocusTraversalKeysSet(int id) Returns whether the Set of focus traversal keys for the given focus traversal operation has been explicitly defined for this Component. |
| 17 | int checkImage(Image image, ImageObserver observer) Returns the status of the construction of a screen representation of the specified image. |
| 18 | int checkImage(Image image,int width,int height, ImageObserver observer) Returns the status of the construction of a screen representation of the specified image. |
| 19 | boolean contains(int x,int y) Checks whether this component "contains" the specified point, where x and y are defined to be relative to the coordinate system of this component. |
| 20 | boolean contains(Point p) Checks whether this component "contains" the specified point, where the point's x and y coordinates are defined to be relative to the coordinate system of this component. |
| 21 | Image createImage(ImageProducer producer) Creates an image from the specified image producer. |
| 22 | Image createImage(int width,int height) Creates an off-screen drawable image to be used for double buffering. |
| 23 | VolatileImage createVolatileImage(int width,int height) Creates a volatile off-screen drawable image to be used for double buffering. |
| 24 | VolatileImage createVolatileImage(int width,int height, ImageCapabilities caps) Creates a volatile off-screen drawable image, with the given capabilities. |
| 25 | void deliverEvent(Event e) Deprecated. As of JDK version 1.1, replaced by dispatchEvent(AWTEvent e). |
| 26 | void disable() Deprecated. As of JDK version 1.1, replaced by setEnabled(boolean). |
| 27 | protected void disableEvents(long eventsToDisable) Disables the events defined by the specified event mask parameter from being delivered to this component. |
| 28 | void dispatchEvent(AWTEvent e) Dispatches an event to this component or one of its sub components. |
| 29 | void doLayout() Prompts the layout manager to lay out this component. |
| 30 | void enable() Deprecated. As of JDK version 1.1, replaced by setEnabled(boolean). |
| 31 | void enable(boolean b) Deprecated. As of JDK version 1.1, replaced by setEnabled(boolean). |
| 32 | protected void enableEvents(long eventsToEnable) Enables the events defined by the specified event mask parameter to be delivered to this component. |
| 33 | void enableInputMethods(boolean enable) Enables or disables input method support for this component. |
| 34 | protected void firePropertyChange(String propertyName, boolean oldValue, boolean newValue) Support for reporting bound property changes for boolean properties. |
| 35 | void firePropertyChange(String propertyName, byte oldValue, byte newValue) Reports a bound property change. |
| 36 | void firePropertyChange(String propertyName, char oldValue, char newValue) Reports a bound property change. |
| 37 | void firePropertyChange(String propertyName, double oldValue, double newValue) Reports a bound property change. |
| 38 | void firePropertyChange(String propertyName, float oldValue, float newValue) Reports a bound property change. |
| 39 | void firePropertyChange(String propertyName, long oldValue, long newValue) Reports a bound property change. |
| 40 | protected void firePropertyChange(String propertyName, Object oldValue, Object newValue) Support for reporting bound property changes for Object properties. |
| 41 | void firePropertyChange(String propertyName, short oldValue, short newValue) Reports a bound property change. |
| 42 | AccessibleContext getAccessibleContext() Gets the AccessibleContext associated with this Component. |
| 43 | float getAlignmentX() Returns the alignment along the x axis. |
| 44 | float getAlignmentY() Returns the alignment along the y axis. |
| 45 | Color getBackground() Gets the background color of this component. |
| 46 | int getBaseline(int width,int height) Returns the baseline. |
| 47 | Component.BaselineResizeBehavior getBaselineResizeBehavior() Returns an enum indicating how the baseline of the component changes as the size changes. |
| 48 | Rectangle getBounds() Gets the bounds of this component in the form of a Rectangle object. |
| 49 | Rectangle getBounds(Rectangle rv) Stores the bounds of this component into return value rv and return rv. |
| 50 | ColorModel getColorModel() Gets the instance of ColorModel used to display the component on the output device. |
| 51 | Component getComponentAt(int x,int y) Determines if this component or one of its immediate subcomponents contains the (x, y) location, and if so, returns the containing component. |
| 52 | Component getComponentAt(Point p) Returns the component or subcomponent that contains the specified point. |
| 53 | ComponentListener[] getComponentListeners() Returns an array of all the component listeners registered on this component. |
| 54 | ComponentOrientation getComponentOrientation() Retrieves the language-sensitive orientation that is to be used to order the elements or text within this component. |
| 55 | Cursor getCursor() Gets the cursor set in the component. |
| 56 | DropTarget getDropTarget() Gets the DropTarget associated with this Component. |
| 57 | Container getFocusCycleRootAncestor() Returns the Container which is the focus cycle root of this Component's focus traversal cycle. |
| 58 | FocusListener[] getFocusListeners() Returns an array of all the focus listeners registered on this component. |
| 59 | Set<AWTKeyStroke> getFocusTraversalKeys(int id) Returns the Set of focus traversal keys for a given traversal operation for this Component. |
| 60 | boolean getFocusTraversalKeysEnabled() Returns whether focus traversal keys are enabled for this Component. |
| 61 | Font getFont() Gets the font of this component. |
| 62 | FontMetrics getFontMetrics(Font font) Gets the font metrics for the specified font. |
| 63 | Color getForeground() Gets the foreground color of this component. |
| 64 | Graphics getGraphics() Creates a graphics context for this component. |
| 65 | GraphicsConfiguration getGraphicsConfiguration() Gets the GraphicsConfiguration associated with this Component. |
| 66 | int getHeight() Returns the current height of this component. |
| 67 | HierarchyBoundsListener[] getHierarchyBoundsListeners() Returns an array of all the hierarchy bounds listeners registered on this component. |
| 68 | HierarchyListener[] getHierarchyListeners() Returns an array of all the hierarchy listeners registered on this component. |
| 69 | boolean getIgnoreRepaint() |
| 70 | InputContext getInputContext() Gets the input context used by this component for handling the communication with input methods when text is entered in this component. |
| 71 | InputMethodListener[] getInputMethodListeners() Returns an array of all the input method listeners registered on this component. |
| 72 | InputMethodRequests getInputMethodRequests() Gets the input method request handler which supports requests from input methods for this component. |
| 73 | KeyListener[] getKeyListeners() Returns an array of all the key listeners registered on this component. |
| 74 | <T extends EventListener> T[] getListeners(Class<T> listenerType) Returns an array of all the objects currently registered as FooListeners upon this Component. |
| 75 | Locale getLocale() Gets the locale of this component. |
| 76 | Point getLocation() Gets the location of this component in the form of a point specifying the component's top-left corner. |
| 77 | Point getLocation(Point rv) Stores the x,y origin of this component into return value rv and return rv. |
| 78 | Point getLocationOnScreen() Gets the location of this component in the form of a point specifying the component's top-left corner in the screen's coordinate space. |
| 79 | Dimension getMaximumSize() Gets the maximum size of this component. |
| 80 | Dimension getMinimumSize() Gets the mininimum size of this component. |
| 81 | MouseListener[] getMouseListeners() Returns an array of all the mouse listeners registered on this component. |
| 82 | MouseMotionListener[] getMouseMotionListeners() Returns an array of all the mouse motion listeners registered on this component. |
| 83 | Point getMousePosition() Returns the position of the mouse pointer in this Component's coordinate space if the Component is directly under the mouse pointer, otherwise returns null. |
| 84 | MouseWheelListener[] getMouseWheelListeners() Returns an array of all the mouse wheel listeners registered on this component. |
| 85 | String getName() Gets the name of the component. |
| 86 | Container getParent() Gets the parent of this component. |
| 87 | java.awt.peer.ComponentPeer getPeer() Deprecated. As of JDK version 1.1, programs should not directly manipulate peers; replaced by boolean isDisplayable(). |
| 88 | Dimension getPreferredSize() Gets the preferred size of this component. |
| 89 | PropertyChangeListener[] getPropertyChangeListeners() Returns an array of all the property change listeners registered on this component. |
| 90 | PropertyChangeListener[] getPropertyChangeListeners(String propertyName) Returns an array of all the listeners which have been associated with the named property. |
| 91 | Dimension getSize() Returns the size of this component in the form of a Dimension object. |
| 92 | Dimension getSize(Dimension rv)Stores the width/height of this component into return value rv and return rv. |
| 93 | Toolkit getToolkit() Gets the toolkit of this component. |
| 94 | Object getTreeLock() Gets this component's locking object (the object that owns the thread sychronization monitor) for AWT component-tree and layout operations. |
| 95 | int getWidth() Returns the current width of this component. |
| 96 | int getX() Returns the current x coordinate of the components origin. |
| 97 | int getY() Returns the current y coordinate of the components origin. |
| 98 | boolean gotFocus(Event evt, Object what) Deprecated. As of JDK version 1.1, replaced by processFocusEvent(FocusEvent) . |
| 99 | boolean handleEvent(Event evt) Deprecated. As of JDK version 1.1 replaced by processEvent(AWTEvent). |
| 100 | boolean hasFocus() Returns true if this Component is the focus owner. |
| 101 | void hide() Deprecated. As of JDK version 1.1, replaced by setVisible(boolean). |
| 102 | boolean imageUpdate(Image img,int infoflags,int x,int y,int w,int h) Repaints the component when the image has changed. |
| 103 | boolean inside(int x,int y) Deprecated. As of JDK version 1.1, replaced by contains(int, int). |
| 104 | void invalidate() Invalidates this component. |
| 105 | boolean isBackgroundSet() Returns whether the background color has been explicitly set for this Component. |
| 106 | boolean isCursorSet() Returns whether the cursor has been explicitly set for this Component. |
| 107 | boolean isDisplayable() Determines whether this component is displayable. |
| 108 | boolean isDoubleBuffered() Returns true if this component is painted to an offscreen image (buffer) that's copied to the screen later. |
| 109 | boolean isEnabled() Determines whether this component is enabled. |
| 110 | boolean isFocusable() Returns whether this Component can be focused. |
| 111 | boolean isFocusCycleRoot(Container container) Returns whether the specified Container is the focus cycle root of this Component's focus traversal cycle. |
| 112 | boolean isFocusOwner() Returns true if this Component is the focus owner. |
| 113 | boolean isFocusTraversable() Deprecated. As of 1.4, replaced by isFocusable(). |
| 114 | boolean isFontSet() Returns whether the font has been explicitly set for this Component. |
| 115 | boolean isForegroundSet() Returns whether the foreground color has been explicitly set for this Component. |
| 116 | boolean isLightweight() A lightweight component doesn't have a native toolkit peer. |
| 117 | boolean isMaximumSizeSet() Returns true if the maximum size has been set to a non-null value otherwise returns false. |
| 118 | boolean isMinimumSizeSet() Returns whether or not setMinimumSize has been invoked with a non-null value. |
| 119 | boolean isOpaque() Returns true if this component is completely opaque, returns false by default. |
| 120 | boolean isPreferredSizeSet() Returns true if the preferred size has been set to a non-null value otherwise returns false. |
| 121 | boolean isShowing() Determines whether this component is showing on screen. |
| 122 | boolean isValid() Determines whether this component is valid. |
| 123 | boolean isVisible() Determines whether this component should be visible when its parent is visible. |
| 124 | boolean keyDown(Event evt,int key) Deprecated. As of JDK version 1.1, replaced by processKeyEvent(KeyEvent). |
| 125 | boolean keyUp(Event evt,int key) Deprecated. As of JDK version 1.1, replaced by processKeyEvent(KeyEvent). |
| 126 | void layout() Deprecated. As of JDK version 1.1, replaced by doLayout(). |
| 127 | void list() Prints a listing of this component to the standard system output stream System.out. |
| 128 | void list(PrintStream out) Prints a listing of this component to the specified output stream. |
| 129 | void list(PrintStream out,int indent) Prints out a list, starting at the specified indentation, to the specified print stream. |
| 130 | void list(PrintWriter out) Prints a listing to the specified print writer. |
| 131 | void list(PrintWriter out,int indent) Prints out a list, starting at the specified indentation, to the specified print writer. |
| 132 | Component locate(int x,int y) Deprecated. As of JDK version 1.1, replaced by getComponentAt(int, int). |
| 133 | Point location() Deprecated. As of JDK version 1.1, replaced by getLocation(). |
| 134 | boolean lostFocus(Event evt, Object what) Deprecated. As of JDK version 1.1, replaced by processFocusEvent(FocusEvent). |
| 135 | boolean mouseDown(Event evt,int x,int y) Deprecated. As of JDK version 1.1, replaced by processMouseEvent(MouseEvent). |
| 136 | boolean mouseDrag(Event evt,int x,int y) Deprecated. As of JDK version 1.1, replaced by processMouseMotionEvent(MouseEvent). |
| 137 | boolean mouseEnter(Event evt,int x,int y) Deprecated. As of JDK version 1.1, replaced by processMouseEvent(MouseEvent). |
| 138 | boolean mouseExit(Event evt,int x,int y) Deprecated. As of JDK version 1.1, replaced by processMouseEvent(MouseEvent).. |
| 139 | boolean mouseMove(Event evt,int x,int y) Deprecated. As of JDK version 1.1, replaced by processMouseMotionEvent(MouseEvent).. |
| 140 | boolean mouseUp(Event evt,int x,int y) Deprecated. As of JDK version 1.1, replaced by processMouseEvent(MouseEvent). |
| 141 | void move(int x,int y) Deprecated. As of JDK version 1.1, replaced by setLocation(int, int). |
| 142 | void nextFocus() Deprecated. As of JDK version 1.1, replaced by transferFocus(). |
| 143 | void paint(Graphics g) Paints this component. |
| 144 | void paintAll(Graphics g) Paints this component and all of its subcomponents. |
| 145 | boolean postEvent(Event e) Deprecated. As of JDK version 1.1, replaced by dispatchEvent(AWTEvent). |
| 146 | boolean prepareImage(Image image,int width,int height, ImageObserver observer) Prepares an image for rendering on this component at the specified width and height. |
| 147 | void print(Graphics g) Prints this component. |
| 148 | void printAll(Graphics g) Prints this component and all of its subcomponents. |
| 149 | protectedvoid processComponentEvent(ComponentEvent e) Processes component events occurring on this component by dispatching them to any registered ComponentListener objects. |
| 150 | protected void processEvent(AWTEvent e) Processes events occurring on this component. |
| 151 | protected void processFocusEvent(FocusEvent e) Processes focus events occurring on this component by dispatching them to any registered FocusListener objects. |
| 152 | protected void processHierarchyBoundsEvent(HierarchyEvent e) Processes hierarchy bounds events occurring on this component by dispatching them to any registered HierarchyBoundsListener objects. |
| 153 | protected void processHierarchyEvent(HierarchyEvent e) Processes hierarchy events occurring on this component by dispatching them to any registered HierarchyListener objects. |
| 154 | protectedvoid processInputMethodEvent(InputMethodEvent e) Processes input method events occurring on this component by dispatching them to any registered InputMethodListener objects. |
| 155 | protected void processKeyEvent(KeyEvent e) Processes key events occurring on this component by dispatching them to any registered KeyListener objects. |
| 156 | protected void processMouseEvent(MouseEvent e) Processes mouse events occurring on this component by dispatching them to any registered MouseListener objects. |
| 157 | protected void processMouseMotionEvent(MouseEvent e) Processes mouse motion events occurring on this component by dispatching them to any registered MouseMotionListener objects. |
| 158 | protected void processMouseWheelEvent(MouseWheelEvent e) Processes mouse wheel events occurring on this component by dispatching them to any registered MouseWheelListener objects. |
| 159 | void remove(MenuComponent popup) Removes the specified popup menu from the component. |
| 160 | void removeComponentListener(ComponentListener l) Removes the specified component listener so that it no longer receives component events from this component. |
| 161 | void removeFocusListener(FocusListener l) Removes the specified focus listener so that it no longer receives focus events from this component. |
| 162 | void removeHierarchyBoundsListener(HierarchyBoundsListener l) Removes the specified hierarchy bounds listener so that it no longer receives hierarchy bounds events from this component. |
| 163 | void removeHierarchyListener(HierarchyListener l) Removes the specified hierarchy listener so that it no longer receives hierarchy changed events from this component. |
| 164 | void removeInputMethodListener(InputMethodListener l) Removes the specified input method listener so that it no longer receives input method events from this component. |
| 165 | void removeKeyListener(KeyListener l) Removes the specified key listener so that it no longer receives key events from this component. |
| 166 | void removeMouseListener(MouseListener l) Removes the specified mouse listener so that it no longer receives mouse events from this component. |
| 167 | void removeMouseMotionListener(MouseMotionListener l) Removes the specified mouse motion listener so that it no longer receives mouse motion events from this component. |
| 168 | void removeMouseWheelListener(MouseWheelListener l) Removes the specified mouse wheel listener so that it no longer receives mouse wheel events from this component. |
| 169 | void removeNotify() Makes this Component undisplayable by destroying it native screen resource. |
| 170 | void removePropertyChangeListener(PropertyChangeListener listener) Removes a PropertyChangeListener from the listener list. |
| 171 | void removePropertyChangeListener(String propertyName, PropertyChangeListener listener) Removes a PropertyChangeListener from the listener list for a specific property. |
| 172 | void repaint() Repaints this component. |
| 173 | void repaint(int x,int y,int width,int height) Repaints the specified rectangle of this component. |
| 174 | void repaint(long tm) Repaints the component. |
| 175 | void repaint(long tm,int x,int y,int width,int height) Repaints the specified rectangle of this component within tm milliseconds. |
| 176 | void requestFocus() Requests that this Component get the input focus, and that this Component's top-level ancestor become the focused Window. |
| 177 | protected boolean requestFocus(boolean temporary) Requests that this Component get the input focus, and that this Component's top-level ancestor become the focused Window. |
| 178 | boolean requestFocusInWindow() Requests that this Component get the input focus, if this Component's top-level ancestor is already the focused Window. |
| 179 | protected boolean requestFocusInWindow(boolean temporary) Requests that this Component get the input focus, if this Component's top-level ancestor is already the focused Window. |
| 180 | void reshape(int x,int y,int width,int height) Deprecated. As of JDK version 1.1, replaced by setBounds(int, int, int, int). |
| 181 | void resize(Dimension d) Deprecated. As of JDK version 1.1, replaced by setSize(Dimension). |
| 182 | void resize(int width,int height) Deprecated. As of JDK version 1.1, replaced by setSize(int, int). |
| 183 | void setBackground(Color c) Sets the background color of this component. |
| 184 | void setBounds(int x,int y,int width,int height) Moves and resizes this component. |
| 185 | void setBounds(Rectangle r) Moves and resizes this component to conform to the new bounding rectangle r. |
| 186 | void setComponentOrientation(ComponentOrientation o) Sets the language-sensitive orientation that is to be used to order the elements or text within this component. |
| 187 | void setCursor(Cursor cursor) Sets the cursor image to the specified cursor. |
| 188 | void setDropTarget(DropTarget dt) Associate a DropTarget with this component. |
| 189 | void setEnabled(boolean b) Enables or disables this component, depending on the value of the parameter b. |
| 190 | void setFocusable(boolean focusable) Sets the focusable state of this Component to the specified value. |
| 191 | void setFocusTraversalKeys(int id, Set<? extends AWTKeyStroke> keystrokes) Sets the focus traversal keys for a given traversal operation for this Component. |
| 192 | void setFocusTraversalKeysEnabled(boolean focusTraversalKeysEnabled) Sets whether focus traversal keys are enabled for this Component. |
| 193 | void setFont(Font f) Sets the font of this component. |
| 194 | void setForeground(Color c) Sets the foreground color of this component. |
| 195 | void setIgnoreRepaint(boolean ignoreRepaint) Sets whether or not paint messages received from the operating system should be ignored. |
| 196 | void setLocale(Locale l) Sets the locale of this component. |
| 197 | void setLocation(int x,int y) Moves this component to a new location. |
| 198 | void setLocation(Point p) Moves this component to a new location. |
| 199 | void setMaximumSize(Dimension maximumSize) Sets the maximum size of this component to a constant value. |
| 200 | void setMinimumSize(Dimension minimumSize) Sets the minimum size of this component to a constant value. |
| 201 | void setName(String name) Sets the name of the component to the specified string. |
| 202 | void setPreferredSize(Dimension preferredSize) Sets the preferred size of this component to a constant value. |
| 203 | void setSize(Dimension d) Resizes this component so that it has width d.width and height d.height. |
| 204 | void setSize(int width,int height) Resizes this component so that it has width width and height height. |
| 205 | void setVisible(boolean b) Shows or hides this component depending on the value of parameter b. |
| 206 | void show() Deprecated. As of JDK version 1.1, replaced by setVisible(boolean). |
| 207 | void show(boolean b) Deprecated. As of JDK version 1.1, replaced by setVisible(boolean). |
| 208 | Dimension size() Deprecated. As of JDK version 1.1, replaced by getSize(). |
| 209 | String toString() Returns a string representation of this component and its values. |
| 210 | void transferFocus() Transfers the focus to the next component, as though this Component were the focus owner. |
| 211 | void transferFocusBackward() Transfers the focus to the previous component, as though this Component were the focus owner. |
| 212 | void transferFocusUpCycle() Transfers the focus up one focus traversal cycle. |
| 213 | void update(Graphics g) Updates this component. |
| 214 | void validate() Ensures that this component has a valid layout. |
| 215 | Rectangle bounds() Deprecated. As of JDK version 1.1, replaced by getBounds(). |
| 216 | protected AWTEvent coalesceEvents(AWTEvent existingEvent, AWTEvent newEvent) Potentially coalesce an event being posted with an existing event. |
| 217 | protected String paramString() Returns a string representing the state of this component. |
| 218 | protected void firePropertyChange(String propertyName,int oldValue,int newValue) Support for reporting bound property changes for integer properties. |
| 219 | Dimension preferredSize() Deprecated. As of JDK version 1.1, replaced by getPreferredSize(). |
| 220 | boolean prepareImage(Image image, ImageObserver observer) Prepares an image for rendering on this component. |
| 221 | Dimension minimumSize() Deprecated. As of JDK version 1.1, replaced by getMinimumSize(). |
继承的方法
这个类继承的方法从以下类：
- java.lang.Object