Java.md

Question List

1.] Output of below code .

public class Main {
    public static void main(String []arg){
        System.out.println(print(1));
    }
    
    static Exception print(int i){
        if (i>0){
            return new Exception();
        }
        else{
            throw new RuntimeException();
        }
    }
}

1. "java.lang.Exception"
2. It will show a stack trace with a runtime exception.
3. It will not compile.
4. It will run and throw an exception.

2.] Which code would you use to tell of "schwiffy" is of type String?

1. "schwiffy".getType().equals("String")
2. "schwiffy".getClass().getSimpleName() == "String"
3. "schwiffy" instanceof String
4. "schwiffy".getType() == String

3.] Given the string "strawberries" saved in a variable cal fruit, what would fruit.substring(2,5) return?

1. awb
2. raw
3. rawb
4. traw

4.] What will this program print out to the console when executed?

public class Main {
    public static void main(String []arg){
        LinkedList<Integer> list = new LinkedList();
        list.add(5);
        list.add(1);
        list.add(10);
        System.out.println(list);               
    }  
}

1. [10, 5, 1]
2. [10, 1, 5]
3. [5, 1, 10]
4. [1, 5, 10]

5.] How do yu write a foreach loop that will iterate over ArrayList pencilCase?

1. for (int i=0; i<pencilCase.size(); i++){}
2. for (pencilCase.next()) {}
3. Iterator iterator = pencilCase.iterator() for (iterator.next())
4. for (Pencil pencil: pencilCase) {}

6.] What is the output of this code?

public class Main {
    public static void main(String []arg){
        String message = "Hello world!";
        String newMessage = message.substring(6, 12)+message.substring(12, 6);
        System.out.println(newMessage);                
    }   
}

1. The code does not compile.
2. "world!!world"
3. "world!world!"
4. A runtime exception is thrown

7.] Give this code, which command will output "2"?

public class Main {
    public static void main(String []arg){
        System.out.println(arg[2]);                
    }   
}

1. java Main 1 "2" "3 4" 5
2. java Main 1 "2" "2" 5
3. java Mian.class 1 "2" 2 5
4. java main 1 2 "3 4" 5

8.] What does this code print?

System.out.println("apple".compareTo("banana"));

1. 0
2. a negative number
3. a positive number
4. false

9.] What can you use to create new instances in Java?

1. another instance
2. private method
3. constructor
4. field

10.] What is the output of this code?

public class Main {
    public static void main(String []arg){
        int a =123451234512345;
        System.out.println(a);                
    }   
}

1. '123451234512345'
2. '12345100000'
3. Nothing--this will not compile.
4. a negative integer number

11.] The runtime system start your program by calling which function first?

1. print
2. iterative
3. hello
4. main

12.] How can you achieve runtime polymorphism in Java?

1. method overriding
2. method overloading
3. method calling
4. method overrunning

13.] Which for loop is invalid?

1. for(int x=1; x<-10; x++){}
2. for(i=3; i<=3; i++){}
3. for(;;){}
4. for(int i; i==2; i++){}

14.] What letters will print when this code is run ?

public class Main {
    public static void main(String []arg){
        try{
            System.out.println("A");
            bedMethod();
            System.out.println("B");
        }
        catch(Exception ex){
            System.out.println("C");
        }finally{
            System.out.println("D");
        }                
    }  
    public static void bedMethod() {
        throw new Error(); //To change body of generated methods, choose Tools | Templates.
    }
}

1. A,C and D
2. C and D
3. A and D
4. A, B, and D

15.] Which is the most up-to-date way to instantiate the current date?

1. LocalDate.now()
2. Calender.getInstance().getTime()
3. new SimpleDateFormat("yyyy-MM-dd").format(new Date())
4. new Date(System.currentTimeMillis())