What will happen if you compile/run the following code?
1: public class Q11
2: {
3: static String str1 = "main method with String[] args";
4: static String str2 = "main method with int[] args";
5:
6: public static void main(String[] args)
7: {
8: System.out.println(str1);
9: }
10:
11: public static void main(int[] args)
12: {
13: System.out.println(str2);
14: }
15: }
A) Duplicate method main(), compilation error at line 6.
B) Duplicate method main(), compilation error at line 11.
C) Prints "main method with main String[] args".
D) Prints "main method with main int[] args".
Answer
What is the output of the following code?
1: class Test
2: {
3: Test(int i)
4: {
5: System.out.println("Test(" +i +")");
6: }
7: }
8:
9: public class Q12
10: {
11: static Test t1 = new Test(1);
12:
13: Test t2 = new Test(2);
14:
15: static Test t3 = new Test(3);
16:
17: public static void main(String[] args)
18: {
19: Q12 Q = new Q12();
20: }
21: }
A) Test(1)
Test(2)
Test(3)
B) Test(3)
Test(2)
Test(1)
C) Test(2)
Test(1)
Test(3)
D) Test(1)
Test(3)
Test(2)
Answer
What is the output of the following code?
1: int i = 16;
2: int j = 17;
3:
4: System.out.println("i >> 1 = " + (i >> 1));
5: System.out.println("j >> 1 = " + (j >> 1));
A) Prints "i >> 1 = 8"
"j >> 1 = 8"
B) Prints "i >> 1 = 7"
"j >> 1 = 7"
C) Prints "i >> 1 = 8"
"j >> 1 = 9"
D) Prints "i >> 1 = 7"
"j >> 1 = 8"
Answer
What is the output of the following code?
1: int i = 45678;
2: int j = ~i;
3:
4: System.out.println(j);
A) Compilation error at line 2. ~ operator applicable to boolean values only.
B) Prints 45677.
C) Prints -45677.
D) Prints -45679.
Answer
What will happen when you invoke the following method?
1: void infiniteLoop()
2: {
3: byte b = 1;
4:
5: while ( ++b > 0 )
6: ;
7: System.out.println("Welcome to Java");
8: }
A) The loop never ends(infiniteLoop).
B) Prints "Welcome to Java".
C) Compilation error at line 5. ++ operator should not be used for byte type variables.
D) Prints nothing.
Answer
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" .
Answer
What is the output of the following code?
1: String str = "Welcome";
2:
3: str.concat(" to Java!");
4:
5: System.out.println(str);
A) Strings are immutable, compilation error at line 3.
B) Strings are immutable, runtime exception at line 3.
C) Prints "Welcome".
D) Prints "Welcome to Java!".
Answer
What is the output of the following code?
1: class MyClass
2: {
3: static int maxElements;
4:
5: MyClass(int maxElements)
6: {
7: this.maxElements = maxElements;
8: }
9:
10: }
11:
12: public class Q19
13: {
14: public static void main(String[] args)
15: {
16:
17: MyClass a = new MyClass(100);
18: MyClass b = new MyClass(100);
19:
20: if(a.equals(b))
21: System.out.println("Objects have the same values");
22: else
23: System.out.println("Objects have different values");
24: }
25: }
A) Compilation error at line 20. equals() method was not defined.
B) Compiles fine, runtime exception at line 20.
C) Prints "Objects have the same values".
D) Prints "Objects have different values";
Answer
1: import java.applet.*;
2: import java.awt.*;
3:
4: public class Q20 extends Applet
5: {
6: Button okButton = new Button("Ok");
7:
8: public void init()
9: {
10: setLayout(new BorderLayout());
11:
12: add("South", okButton);
13: add("North", okButton);
14: add("East", okButton);
15: add("West", okButton);
16: add("Center", okButon);
17:
18: setSize(300,300);
19: }
20: }
The above Applet will display
A) Five Buttons with label "Ok" at Top, Bottom, Right, Left and Center of the Applet.
B) Only one Button with label "Ok" at the Top of the Applet.
C) Only one Button with label "Ok" at the Bottom of the applet.
D) Only one Button with label "Ok" at the Center of the Applet.
Answer
B. Here the variable 'b' will go upto 127.
After that overflow will occur, so 'b' will be set to -ve value, the loop ends and prints "Welcome to Java" Back to Question 15
C. Strings are immutable. So str.concat("to Java!") will not append anything to str.
Infact it will create another string "Welcome to Java!" and leaves it. Back to Question 18
D. equals() method was available in base class Object. So it won't give any compilation error.
Here MyClass is a user-defined class, so the user has to implement equals() method according to his requirments. Back to Question 19
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