First Class which is giving me the error. I'm to make an array with the letters A-Z, and then have the user input the keys which it takes and compares each character's position in the array of the key with the position of a user inputted string
import java.util.*;
public class Encrypt{
private Square plain1;
private Square plain2;
private Square Encrypt1;
private Square Encrypt2;
public Encryption(String key1, String key2) {
Square plain1 = new Square();
Square plain2 = new Square();
Square Encrypt1= new Square(key1);
Square Encrypt2= new Square(key2);
}
public String encrypt(String msg) {
String EmpS = "";
String STR = "";
for(int i = 0; i < message.length(); i =2){
char iMsg = message.charAt(i);
char iMsg2 = message.charAt(i 1);
int[] posRay = plain1.findPosition(iMsg);
int[] posRay2 = plain2.findPosition(iMsg2);
String answer = "" Encrypt1.getChar(posRay[0], posRay2[1]);
String Combined = "" answer;
String answer2 = "" Encrypt2.getChar(posRay2[0], posRay[1]);
String Combined2 = "" answer2;
String BothCom = Combined Combined2;
STR = STR.concat(BothCom);
return STR;
}
return STR;
}
2nd class that is responsible for the array
public class Square {
private char[][] matrix;
public Square() {
arr= new char[5][5];
int ascii= 65;
for (int i = 0; i < 5; i ){
for(int j = 0; j < 5; j ){
arr[i][j] = (char) ascii;
ascii ;
}
}
}
}
public int[] findPosition(char Chart) {
int[] position= new int[2];
position[0] = -1;
popositions[1] = -1;
for (int i = 0; i < 5; i ){
for (int j = 0; i < 5; j ){
if(matrix[i][j] == Chart){
posistion[0] = i;
position[1] = j;
return position;
}
}
}
I'm getting this as an error (everything else works), what's the issue?:
Exception in thread "main" java.lang.NullPointerException: Cannot invoke "Square.getPos(char)" because "this.plain1" is null
at findPosition.encrypt(Encrypt.java:45)
at IO.printResults(IO.java:101)
at Test.main(Proj8.java:26)
CodePudding user response:
You are not assigning your class variables, you are actually assigning new local variables inside the method. Change to:
public Encryption(String key1, String key2) {
plain1 = new Square();
plain2 = new Square();
Encrypt1= new Square(key1);
Encrypt2= new Square(key2);
}