Java Programming - 4.1 Decision making statement

1. What will be the output of following JAVA code?
public class If_1
{
public static void main(String args[])
{
String a="Learning JAVA_IF";
if ("Learn with Durga".contains("earn"))
System.out.println(a);
else
System.out.println("Never stop Learn");
}
}
Output:
Learning JAVA_IF
Explanation:
If condition checks the string in-built method "Learn with Durga" has sub-string "earn" and it returns true; If statement satisfies true part and it prints value of a.

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2. What will be the output of following JAVA code?

public class If_2{

public static void main(String args[]){
int a=5;
if(a<0){
if (a<5)
System.out.println(a);
else
System.out.println(++a);
}
System.out.println(a++);
}
}
Output:
5
Explanation:
Outer if statement fails the condition, so it comes out of the entire if scope and executes SOP statement outside of the scope.

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3. What will be the output of following JAVA code?

public class If_3

{
static boolean bo;
public static void main(String args[])
{
int b=87;
if (bo)
System.out.println(b);
else
System.out.println(++b);
}
}
Output:
88
Explanation:
Boolean variable bo is an instance variable of class If_3 and it initializes the default value of boolean (false). If statement checks the boolean value and prints else part value ++b (b=88).

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4. What will be the output of following JAVA code?
public class If_4
{
public static void main(String args[])
{
boolean x = true;
        boolean y = false;
        if (x && y) {
            System.out.println(true);
        } else {
            System.out.println(false);
        }
}
}
Output:
false
Explanation:
If condition checks logical AND operation of x and y and it returns false, prints false.
Note: Logical AND doesn't checks the second part of operation if the first part is false.

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5. What will be the output of the JAVA code, when choice is 1? 
public class Switch_1
{
public static void main(String args[])
{
int choice=1;
switch (choice){
case '1':System.out.print("Learn");break;
case '2':System.out.print("with");break;
case '3':System.out.print("Durga");break;
default:System.out.print("keep learning");
}
}
}
Output:
Keep learning
Explanation:
Integer variable choice doesn't matches with the cases inside switch; So, it prints default statement.

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6. What will be the output of the following JAVA code?
public class Switch_2
{
public static void main(String args[]){
         int print= 3;
        switch (print){
                        case 1:case 3:case 5: System.out.print("Odd I am"); break;
                        case 2:case 4:case 6:System.out.print("Even I am"); break;
                        default:System.out.print("Neither odd nor even");
}
}
}
Output:
Odd I am
Explanation:
Switch statement supports nested case statement, make sure that same case doesn't have different definition in another nested case.

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7. What will be the output of following JAVA code?

public class Switch_3

{
public static void main(String args[])
{
int pick=14;
switch (pick){
case 7+7:System.out.print("Learn ");
case 8+7:System.out.print("with ");
case 9+7:System.out.print("Durga ");
default:System.out.print("keep learning");
}
}
}
Output:
Learn with Durga keep learning
Explanation:
Switch case supports constant expression and it doesn't allow neither variable nor variable expression.

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