Core java interview Questions You'll Most Likely Be Asked (Second Edition)

Which of the following lines of code will compile and
which will cause an error?
int iValue=5;
while (iValue) {} //Line 1
while (false) {} //Line 2
while (iValue = 5) {} //Line 3
while (iValue == 5) {} //Line 4
Answer:
Line 1 will cause an error because an integer value cannot be
passed to a while loop. It requires a boolean value.
Line 2 compiles fine since the boolean value false is used in
the while loop
Line 3 causes a compilation error since the expression
iValue=5 does not evaluate to a boolean value, it is an
assignment statement

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054.
Line 4 compiles file since the expression iValue==5 evaluates
to a boolean value.
What would be the output if boolA is false and boolB is
true?
public void foo( boolean boolA, boolean boolB) /* Line 1
*/
{
if(boolA ) {/* Line 3 */
System.out.println(“X”); /* Line 5 */
}
else if(boolA && boolB) {/* Line 7 */
System.out.println( “X && Y”); /* Line 9 */
}
else { /* Line 11 */
if (!boolB ){ /* Line 13 */
System.out.println( “notY”); /* Line 15 */
}
else{ /* Line 17 */
System.out.println( “In here” ); /* Line 19 */
}
}
}
Answer:
Output: In here
Since boolA is false, line 5 will never execute and X will not be
printed. Since boolA is false line 7 will also not execute and so X
&& Y will also not be printed. The else block at line 11 will be
entered. Since boolB is true, the if statement at line 13 is not

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055.
executed. So, the else statement at line 13 is executed which
prints In here.
What will be the output of the following program?
public class SwitchDemo
{
final static short caseVal = 2;
public static void main(String [] abc)
{
for (int iterNo=0; iterNo < 3; iterNo ++) {
switch (iterNo) {
case caseVal– System.out.print(“a “);
case caseVal–1– System.out.print(“b “);
case caseVal–2– System.out.print(“c “);
}
}
}
}