InstanceOfJava

Format text using printf() method in java

Posted by: Instanceofjava Posted date: 12:29 AM / comment : 0 Core java Interview Questions

printf method in java:

Print() and println() methods are used to print text and object values or format data.
In order to format text we also have printf() method in java
Formatting data means displaying corresponding data type value.
For example when print float ot double value if we want to specify upto 2 decimal numbers we user.
System.out.printf("%.2f", variable);
Also alignment of string data. when we are printing string data in java using print() and pintf()

#1. Write a program to print string using print() and printf() methods

package printfinjava;
/**
* How to format text using java printf() method
* @author www.instanceofjava.com
*/
public class PrintfMethod {
public static void main(String[] args) {
String str="java printf double";
System.out.println ("String is "+str);
System.out.printf ("String is %s", str);
}
}

Output:

String is java printf double
String is java printf double

java printf table

Format double using printf():

We can format double using printf() method in java
format double to 2 decimal places in java possible by using system.out.printf() method.

#2. Write a program to print double to 2 decimal places in java

package printfinjava;
/**
* How to format text using java printf() method
* @author www.instanceofjava.com
*/
public class PrintfMethod {
public static void main(String[] args) {
double value=12.239344;
System.out.printf("%.2f", value);
}
}

Output:

12.24

#3. Write a program to format text using printf() method in java

5 Different ways to print arrays in java

Posted by: Instanceofjava Posted date: 11:53 AM / comment : 0 arrays

Arrays in java are used to hold similar data types values.
System.out.print() method does not print values of array.
In order to print array values we have different ways.
Normally we use for loop and by using index we will print each element inside array.
let us see how many ways we can able to print values of array.

1.Print array in java using for loop

How to print array in java using for loop?
Yes we can print arrays elements using for loop.
Find the length of the array using array.length and take initial value as 0 and repeat until array.length-1.
Then access each index values of an array then print.

#1. Write a program to print array in java using for loop

package arraysinterview;
public class PrintArray {
/**
* How to print java array using for loop
* @author www.instanceofjava.com
*/
public static void main(String [] args){
int[] array = { 12,13,8,34,2,7,9,43,54,21};
for (int i = 0; i < array.length; i++) {
System.out.println(array[i]);
}
}
}

Output:

2. Print string array in java using Enhanced for loop

From java 1.5 using enhanced for loop also we can print array values.

#2. How to print string array in java using for each loop

3. Using Arrays.toString(array) method

By using Arrays.toString(array) method we can print array values.

#3 Write a program to print array in java using Arrays.toString(array)

package arraysinterview;
import java.util.Arrays;
public class PrintArray {
/**
* How to print java array using Arrays.toString(array)
* @author www.instanceofjava.com */
public static void main(String [] args){
String[] array = { "hi", "hello", "java"};
System.out.println(Arrays.toString(array));
}
}

Output:

[hi, hello, java]

4.Using Arrays.deepToString(array) Method

Arrays,deepToString(array) method added in java 5 with generics and varargs.

#4 Write a program to print array in java using Arrays.deepToString(array)

package arraysinterview;
import java.util.Arrays;
public class PrintArray {
/**
* How to print java array using Arrays.deepToString(array)
* @author www.instanceofjava.com */
public static void main(String [] args){
int[][] array = new int[][]{
{1,2,3},
{11,12,13},
{4 ,5,6},
};
System.out.println(Arrays.deepToString(array));
}
}

Output:

[[1, 2, 3], [11, 12, 13], [4, 5, 6]]

5.Using Arrays.asList(array) Method

Arrays,asList(array) method we can print array elements

#5 Write a program to print array in java using Arrays.asList(array)

package arraysinterview;
import java.util.Arrays;
public class PrintArray {
/**
* How to print java array using Arrays.asList(array)
* @author www.instanceofjava.com */
public static void main(String [] args){
int[] array ={1,2,3,4,5,6};
System.out.println(Arrays.asList(array));
String[] strarray ={"hi","array","print"};
System.out.println(Arrays.asList(strarray));
}
}

Output:

[[I@2a139a55]
[hi, array, print]

Exception handling multiple choice interview questions and answers in java

Posted by: Instanceofjava Posted date: 2:50 PM / comment : 0 core java multiple choice questions with answers , exception handling interview questions

1.Exceptions Occurs at

Compile time

Run time

2.what is the Super class of Exception class?

Object

Throwable

Error

3.We can have try block without catch block

Yes

4.Is it possible to write multiple exceptions in single catch block

Yes from java 7

Java objective type questions and answers on static keyword

Posted by: Instanceofjava Posted date: 8:46 PM / comment : 0 core java multiple choice questions with answers

1.Static means

Class level

Object level

2.Main method is static because to execute main method without creating object By JVM

Yes

3.We can overload static methods

True

False

4.We can override static methods

Yes

5.Can we write static public void main(String [] args)?

Yes

6.What is the output of below program ?

java multiple choice questions with answers

x=10 x=10

x=10 x=20

x=30 x=30

x=30 x=20

Java mcq with answers on this keyword

Posted by: Instanceofjava Posted date: 9:11 PM / comment : 0 core java multiple choice questions with answers

1.this always will points to

Current class object

Super class object

2.We can use this in static methods?

True

False

3.Can we call static methods using this from non static methods

Yes

4.We can return this from a method as return type

True

False

5.What is the output of below program

Hello instanceofjava

compile time error

Run time exception

Core java multiple choice questions with answers on method overloading

Posted by: Instanceofjava Posted date: 7:34 PM / comment : 0 core java multiple choice questions with answers

1.Method overloading means?

Multiple methods with same name same arguments

Multiple methods with same name different arguments

Multiple methods with different name different arguments

2.Method overloading also known as?

Dynamic polymorphism

Static polymorphism

3.Can we overload main method?

Yes

4.Which is incorrect statement regarding overloading?
(which is incorrect about method overloading)

Method with same name and differ in number of arguments

Methods should be with same name and different return type

Methods should be same name and differ in order of type of arguments

Methods should be with same name and differ in type of arguments

5.What is the output of below program?

hello

compile time error

Run time exception

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