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awt

Jeannie Yong
Greenhorn

Joined: Oct 18, 2001
Posts: 19
In the following applet, how many Buttons will be displayed?
1: import java.applet.*;
2: import java.awt.*;
3:
4: public class Q16 extends Applet
5: {
6: Button okButton = new Button("Ok");
7:
8: public void init()
9: {
10: add(okButton);
11: add(okButton);
12: add(okButton);
13: add(okButton);
14:
15: add(new Button("Cancel"));
16: add(new Button("Cancel"));
17: add(new Button("Cancel"));
18: add(new Button("Cancel"));
19:
20: setSize(300,300);
21: }
22: }
A) 1 Button with label "Ok" and 1 Button with label "Cancel" .
B) 1 Button with label "Ok" and 4 Buttons with label "Cancel" .
C) 4 Buttons with label "Ok" and 1 Button with label "Cancel" .
D) 4 Buttons with label "Ok" and 4 Buttons with label "Cancel" .
the answer is B, why?
Valentin Crettaz
Gold Digger
Sheriff

Joined: Aug 26, 2001
Posts: 7610
because an instance of a Component can only be added once to a container. Here you are trying to add okButton several times.
Concerning the Cancel buttons, you add a new instance each time you invoke add.
HIH
------------------
Valentin Crettaz
Sun Certified Programmer for Java 2 Platform


SCJP 5, SCJD, SCBCD, SCWCD, SCDJWS, IBM XML
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subject: awt