Abdullah Al Mubin Abdullah Al Mubin - 1 year ago 90
Java Question

NullPointerException at LexicalAnalyzer in Java

My code is this-

package LexicalAnalyzer;

import java.util.Scanner;

public class MainClass {
public static void main(String args[]){
String i = null;
String in = null;
for( ; !i.equals(";;"); ){
Scanner inpu = new Scanner(System.in);
int j = in.length();



Token t=new Token();

I am getting this error for my code-

"Exception in thread "main" java.lang.NullPointerException
at LexicalAnalyzer.MainClass.main(MainClass.java:9)
Java Result: 1"

Can anyone please help me to find out the error?


Mox Mox
Answer Source

i is null, therefore calling the equals function on a null object will result in null pointer exception

you may want to set i to an empty string with

String i = "";

this will instantiate the string with a valid object reference. And now you can access the equals method

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