Sams Teach Yourself C in 21 Days

12:

13: public static void main(String args[]) {

14: AWT_Test1 Test = new AWT_Test1(“A Java Window”);

15: Test.resize(350,250);

16: Test.show();

17: }

18: }

(see Figure B6.1)

750 Bonus Day 6

LISTINGB6.3 continued

OUTPUT

FIGUREB6.1

The output of the pro-

gram in Listing B6.3.

Line 1 of this program imports the classes in the AWT. Line 3 declares the class

(program)AWT_Test1to be a subclass of Frame. Lines 6 through 10 form the

class constructor, which is declared to take one type Stringargument that is the win-

dow’s title. Line 7 uses the superkeyword to pass the title to the superclass construc-

tor—in other words, the constructor method of the Frameclass (see the sidebar for more

onsuper). Other code in the constructor creates a new label object with the text “Hello

from Java”(line 8), defines the font and font size for the label (line 9), and adds the

label at the center of the window (line 10).

In the mainmethod, line 14 creates a variable named Testand initializes it with a new

instance of the class AWT_Test1. Creating a new instance calls the class constructor (lines

6 through 10), passing it the string “A Java window”which is then passed up to the

superclass constructor, as described above. Line 15 sets the window size to 350×250 pix-

els. Finally, line 16 displays the window onscreen.

You can see that Java AWT graphics are completely object based, which is in perfect

keeping with the object-oriented nature of Java itself.

ANALYSIS

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