What can cause the \\\"cannot find symbol\\\" error in Java?

In Java, the cannot find symbol error occurs when we try to reference a variable that is not declared in the program or when we try to access a class that is not declared or imported. 

Possible Causes of 'Cannot Find Symbol' Error

Below is a list of some possible causes of the 'cannot find symbol' error in Java -

• Using a variable that is not declared or outside the code.
• Using wrong cases ("tutorials" and "Tutorials" are different) or making spelling mistakes.
• The packaged class has not been referenced correctly using an import declaration.
• Using improper identifier values like letters, numbers, underscore, and dollar sign. The hello-class is different from helloclass.

Example 1

If a variable is not declared in Java, the compiler will throw a cannot find symbol error.

In the following program, we are trying to print the value of the variable sum, which has not been declared. As a result, the compiler will throw a cannot find symbol error -

public class CannotFindSymbolTest {
   public static void main(String[] args) {
      int n1 = 10;
      int n2 = 20;
      sum = n1 + n2;
      System.out.println(sum);
   }
}

Output

The above program throws the following error -

main.java:5: error: cannot find symbol
sum = n1 + n2;
    ^
symbol:   variable sum
location: class CannotFindSymbolTest
CannotFindSymbolTest.java:6: error: cannot find symbol
    System.out.println(sum);
                       ^
symbol:   variable sum
location: class main
2 errors

Example 2

If a class from a package is not correctly referenced using an import statement in Java, the compiler will throw a cannot find symbol error.

Here is another program that also causes a cannot find symbol error. We are instantiating the Scanner class, but we have not imported the package java.util.Scanner so that the compiler will throw an error -

public class main{
   public static void main(String[] args) {
      Scanner sc = new Scanner(System.in);
      int n = sc.nextInt();
      System.out.println(n);
   }
}

Output

The above program throws the following error -

main.java:3: error: cannot find symbol
Scanner sc = new Scanner(System.in);
    ^
symbol:   class Scanner
location: class main
main.java:3: error: cannot find symbol
    Scanner sc = new Scanner(System.in);
                     ^
symbol:   class Scanner
location: class main
2 errors

Example 3

Since Java is a case-sensitive language, the compiler will throw a cannot find symbol error if a variable is referenced using a different case than it was declared -

public class main {
   public static void main(String[] args) {
      String name = "xyd";
      System.out.println(Name);
   }
}

Output

Following is the output of the above program -

main.java:4: error: cannot find symbol
System.out.println(Name);
                       ^
symbol:   variable Name
location: class main
1 error