Ans : 

Use the getSize method (or size in the JDK 1.0.2), which the Applet class inherits from the Component class  in the java.awt package.

     The getSize method (in JDK 1.1) returns the size of the applet as a Dimension object, from which you can extract separate width and height fields:

     /* Using JDK 1.1: */ 
     Dimension dim = getSize();
     int appletWidth = dim.width;
     int appletHeight = dim.height;

In the JDK 1.0.2, use the method name size in place of getSize.

Ans : 

Use the setBackground method, which the Applet class inherits from Component.

     Component's setBackground method specifies the background color for an AWT component. For applets, this sets the color with which the entire applet area is covered before anything else is drawn on top (lines, images, or even other components, such as buttons and text fields).
     Unless you're changing background colors repeatedly, you should set the background color in your applet's init method:

     public void init() {
     	// ...
    	setBackground(Color.green);
     	// ...
     }

You can also set a background image for the applet, on top of which you place any user-interface components the applet may require

Ans : 

You can't create transparent backgrounds for applets in the JDK (1.0.2 and 1.1), but you can fake it in some cases.

     Applets inherit from the Component class. In the JDK 1.0.2, Component instances are always opaque. (The JDK 1.1 provides the basic infrastructure for lightweight components that can have transparency, but instances of the Applet class still come with an opaque background.) Even if an applet doesn't draw itself in any interesting way, it still fills its rectangular space with a solid background color. The only way to achieve the effect of transparent background is by a chameleon trick: attempt to make your applet's background indistinguishable from the underlying html page background. Yes, this is a hack rather than a solution, but you might find it useful.
     If the html background is a solid color, your work is fairly easy. You can write your applet such that it takes background color as one of its parameters. Then set that parameter in the APPLET tag to match to color of the html page you are putting the applet in.
     If the html page background is a GIF image or pattern, you're basically out of luck. You can still write your applet to take the relevant information as a parameter (in this case, the name of the GIF file that is providing the background image), but your applet's location on the page may cause noticeable discontinuities in the background image. Some patterns are easier to blend in with than others.

Ans : 

No; you can't put a menu bar (or menus) directly on the applet itself.

     The JDK (1.0.2 and 1.1) restricts menu bars to occur only on frames (instances of the Frame class or a Frame subclass). Frames represent independent top-level windows with a border. The Applet class inherits from Panel rather than Frame, though.
     To provide a menu bar for your applet, the current workaround is to create a new Frame instance from your applet and put a menu bar on that. For example:

     import java.awt.*;

     public class AppletMenuExample extends java.applet.Applet {
     	static final String FILE = "File";
    	static final String FILE_NEW = "New...";
    	static final String FILE_OPEN = "Open...";
  	// ...
    	AppletMenuFrame myFrame;
	MenuBar myMenuBar;
	Menu fileMenu;

    public void init() {
        	myFrame = new AppletMenuFrame(this,
                                             "Applet frame with a menu");
        	myMenuBar = new MenuBar();
        	fileMenu = new Menu(FILE);
        	myFrame.setMenuBar(myMenuBar);
        	myMenuBar.add(fileMenu);
        	fileMenu.add(FILE_NEW);
        	fileMenu.add(FILE_OPEN);
        	// ...
        	myFrame.pack();
        	myFrame.show();
        }
     }

Ans : 

In the JDK 1.0.2 you must find the Frame instance that contains the applet and change its cursor, but the JDK 1.1 allows you to set the cursor for instances of any Component subclass, including Applet.

     The JDK 1.0.2 lets you control one cursor per Frame instance. (The Frame class represents top-level, bordered windows.) Since applets aren't a kind of Frame, you can't set the cursor for an applet directly. You can, however, trace up the containment hierarchy until you finally find a Frame instance:

     /* using JDK 1.0.2: */
     Frame myFrame;
     Container parent = getParent();
     while (parent != null &&  !(parent instanceof Frame)) {
     	parent = parent.getParent();
     }
     myFrame = (Frame)parent;
     if (myFrame != null) {
         myFrame.setCursor(Frame.CROSSHAIR_CURSOR);
     }

     The JDK 1.1 fixes this shortcoming by letting you set the cursor on individual components. You can set your applet's cursor by invoking Component's setCursor method on the applet itself. For example:

     /* using JDK 1.1: */
     public void init() {
           setCursor(new Cursor(Cursor.HAND_CURSOR));
            // ...
     }

     An additional benefit of the cursor-per-component service in the JDK 1.1 is that the AWT automatically switches the cursor as needed to match the component pointed to by the mouse. In contrast, the JDK 1.0.2 forces you to manage the cursor switching by yourself, which is doable but tedious.

Ans : 

The key to fixing flicker is realizing that the screen isn't actually painted in the paint() method. The pixels get put on the screen in the update() method which most applets don't override. However by overriding the update() method you can do all your painting in an offscreen Image and then just copy the final Image onto the screen with no visible flicker.
The cookbook approach is simple. Add the following three private fields to your applet and the public update() method. Flicker will magically disappear. 

private Image offScreenImage;
private Dimension offScreenSize;
private Graphics offScreenGraphics;

public final synchronized void update (Graphics g) {

       Dimension d = size();
       if((offScreenImage == null) || (d.width != offScreenSize.width) || (d.height != offScreenSize.height)) {
                offScreenImage = createImage(d.width, d.height);
                offScreenSize = d;
                offScreenGraphics = offScreenImage.getGraphics();
       } 
       offScreenGraphics.clearRect(0, 0, d.width, d.height);
       paint(offScreenGraphics);
       g.drawImage(offScreenImage, 0, 0, null);
}

Ans : 

You can simply do a g.drawImage(yourImage, x, y, this) in the paint() routine of your applet. If the image isn't big enough to fill the entire background, tile it or scale it. Here is some code to tile it

// The background image is named "bg".
int w = 0, h = 0;
while (w < size().width) {
    g.drawImage(bg, w, h, this);
    while ((h + bg.getHeight(this)) < size().height) {
          h += bg.getHeight(this);
          g.drawImage(bg, w, h, this);
     }
     h = 0;
    w += bg.getWidth(this);
}

Alternatively, the AWT can scale your background image to the size of the applet. The result quality will depend on the kind of image. Inside an applet class, you can use:

drawImage(img, 0, 0, size().width, size().height, this);

You can set the background color to match the background color of the browser by passing the value in as a parameter, like this: In the HTML applet tag:
<param name=BrowserColor value=F1F1F1>
(value should be the same hex as the HTML COLOR value).
In the Applet init() method:

String colparam = getParameter("BrowserColor");
int col = Integer.valueOf(colparam,16).intValue();
setBackground( new Color(col) );

An applet cannot override the size imposed by the HTML. If you make the applet larger, the browser will still clip to the original size. If you need more room, open up a new Frame, Window or Dialog to show your output.

Ans : There is no way to give an applet a transparent background that lets the web browser background show through. You can simulate it by giving the applet a background that matches the underlying browser
background. (For a straight color, it will be the value of <BODY BGCOLOR=nnnnnn> in the HTML file). It doesn't produce satisfactory results with a patterned background because of problems aligning the edges.
Lightweight components (new in JDK 1.1) have a transparent background, but that merely allows other components to show through. A lightweight component is always ultimately positioned in a heavyweight component.

Ans :  

In your applet's init() method, create a Frame instance and then attach the Menus, 

Menubar etc to that frame. You cannot attach the Menu
     or a Menubar to an applet directly.
     Or get the parent Frame like this (doesn't work in all execution
     environments):

         Container parent = getParent();
         while (! (parent instanceof Frame) )
             parent = parent.getParent();
         Frame theFrame = (Frame) parent;

This second suggestion definitely doesn't work in the appletviewer, and probably won't work on Macs 

(where would the Menubar go?) or in some browsers. In JDK 1.1, just use a popup menu, which isn't 

attached to a  Frame.

Ans :  

Use some code like this:

void center(Component parent) {
      pack();
      Point p = parent.getLocation();
      Dimension d = parent.getSize();
      Dimension s = getSize();
      p.translate((d.width - s.width) / 2, (d.height - s.height) / 2);
      setLocation(p);
}

Ans :  

If you want resizing behavior from an applet, you should launch an external Frame that can be resized independently.
One programmer suggests using percentages for the height/width parameters in an applet tag, like this:

<APPLET CODE="lewinsky.class" WIDTH="100%" HEIGHT="100%">

You can't resize the applet directly, but it does get resized when you resize the browser window (tested with Netscape 3.04 and 4.04, but does not work with appletviewer). If you have nothing else on your HTML page and use 100% for your width and height, the browser window looks almost like a real application. For the extremely tricky: have the browser reload the page with the applet when the browser resizes using new values for width and height (probably not what you want most of the time). You would need Javascript to generate a page dynamically using document.write("...") when the browser resizes. Not recommended. Another possibility is to use the new SplitPane class in JFC.

Ans :  

Things like background color (and font size, color, etc.) are either set by parameter variables or hard-coded. 

If they are set by the parameters, there will be <PARAM> tags inside the <APPLET></APPLET> tags that look something like: 

<APPLET CODE="myApplet.class">
<PARAM fontcolor="FFFFCC">
<PARAM bgcolor="CCCCCC">
</APPLET>

Now the names of the variables are determined by the programmer, and they may be something cryptic, like "fc" and "bgc". Look at the HTML that displays the applet, and look at the readme files or any other documentation, and see if there is any mention of parameter tags that can be used to change the background. If you don't (and most of the time you won't) then the values are hard-coded. 

If they are hard-coded, you would need access to the .java files that contain the actual Java code. If you have the file(s), you can probably find where the colors are set. You can then change the numbers and recompile with a Java compiler. You can get a free compiler from java.sun.com 

If you don't have access to the source code, however, you're out of luck.