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

048.
049.
i++; // sets i to 11
The decrement operator is represented by two minus signs. It
decrements its operand by 1. The following code demonstrates
this:
int i = 10;
i::; // sets i to 9
Explain the instanceOf operator.
Answer:
The instanceOf operator can be used to check if an object is
an instance of another class. It returns a boolean value. If both
the objects being compared are of same type it returns true and
otherwise it returns false. The following code demonstrates this:
String str = “Hello”;
str instanceof String //returns true
String str = null;
str instanceof String //returns false
Explain the ternary operator with a code sample.
Answer:
The ternary operator is also called as a conditional operator. It is
a short cut operator for the if–else statement. Its syntax is as
follows:
condition?TruePath:FalsePath
It evaluates a condition and if true, it executes code after the “?”
symbol. If false, it executes the code after the “–” symbol. The
following code demonstrates this:

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int iValue1 = 100;
int iValue2 = (iValue1 == 100) ? 200: 100; //Line 1
Here, the iValue==100 condition is evaluated. Since is it true,
the value 200 will be assigned to the variable iValue2.

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050.
a.
b.
CHAPTER
05
Control Statements
Name the decision statements used in Java.
Answer:
Decision statements evaluate an expression and based on the
result, perform the execution. There are two decision statements
in Java. They are:
if: The if else is a conditional branch statement. It tests a
condition and if the condition is true, execution follows a
certain path and if not, it follows a different path. It has the
following syntax:
if(condition){
//some code here
}
else { // this part is optional
//some code here
}
switch: The switch statement is a multi–way branch
statement. It can be used instead of using several if else
statements. The expression specified within the switch
statement is evaluated and matched with every case value.
Once a match is found, the code within the body of that case
statement is executed. It has the following syntax:
switch(expression) {

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051.
a.
b.
case value1:
//some code
break; //optional
case value2:
//some code
break; //optional
…..
case valuen:
//some code
break; //optional
default:
//some code
break; //optional
}
}