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Java

Posted by Fabian Rodriguez
Fabian Rodriguez
Courses Plus Student 859 Points

NullPointerException

package javaapplication2;

import java.io.Console;

public class JavaApplication2 { public static void main(String[] args) { Console console = System.console();

String yourName = console.readLine("Write your name here:   ");
console.printf("Hi, %s %n, it's great to have you here", yourName);

}

}

2 Answers

Patrik Horváth
Patrik Horváth
11,110 Points

If this is JAVA you should use "+" to Combine Strings so

I dont recommended using Console because it not supported by IDEs but OKey :) maybe your lern java for android :)

console.printf("Write your name here:"); // you post msng for user in CONSOLE 
String yourName = System.console().readLine();  // i will wait on your input :D
console.printf("Hi, %s %n, it's great to have you here" + yourName); // you print output
Fabian Rodriguez
Fabian Rodriguez
Courses Plus Student 859 Points

Thank you very much, so instead of using console, what should I use? If I'm using IDE

Patrik Horváth
Patrik Horváth
11,110 Points

System.out for Output and System.in for Input for example

System.out.println("YOUR StRING or StRING OBJECT");

System.in.Scanner(); // this is good for looping in WHILE until you press enter fo example :)

Sławomir Lasik
Sławomir Lasik
7,792 Points
Sławomir Lasik
Sławomir Lasik
7,792 Points

Your code is compiling and running. Try to run it again

It may direct to null only when no console is available to give for the Current JVM.

If this virtual machine has a console then it is represented by a unique instance of this class which can be obtained by invoking the System.console() method. If no console device is available then an invocation of that method will return null.

to check for this option try this

import java.io.Console;
import java.lang.NullPointerException;

public class JavaApplication2 {

 public static void main(String[] args) {
    Console console = null;
    try{

        console = System.console();
        if(console== null) {
            throw new NullPointerException();
        }
    }catch(NullPointerException e){
        System.out.printf("NullPointerException catched! No console avaible for this JVM%n");
    }

    String yourName = console.readLine("Write your name here:   ");
    console.printf("Hi, %s %n, it's great to have you here", yourName);

    }
}