The Cannot Find Symbol Error in Java error occurs when the Java compiler cannot find a symbol that you are trying to reference in your code. In this article, we will explore how to resolve the “Cannot Find Symbol” error in Java.
The “Cannot Find Symbol” error occurs when you are trying to reference a symbol that has not been defined or imported properly. Symbols can include variables, methods, and classes or in easy language when you try to reference an undeclared variable in your code. The error typically occurs when you have made a typo, used the wrong case in the symbol name, or when you are trying to reference a symbol that is out of scope. You may also encounter this error when you are using multiple files, and the compiler cannot find a class or package that you are trying to reference.
Common mistakes that lead to “Cannot Find Symbol” error in Java and resolving them, you can follow these steps:
- Typos
- Undeclared Variable
- Scope of Current block
- Import Statement
Typos
Make sure that the symbol you are trying to reference is spelled correctly and matches the case used in the definition.
Example 1:
Java
// Java Program to demonstrate typospublic class Main { static int Large(int a, int b) { if (a > b) { return a; } else if (b > a) { return b; } else { return -1; } } public static void main(String... args) { int value = large(20, 4); System.out.println(value); }} |
Output:
./Main.java:17: error: cannot find symbol
int value = large(20, 4);
^
symbol: method large(int,int)
location: class Main
Explanation of the above program
We get this error as the function we initialized is Large(int a,int b) whereas we are calling large(a,b) so to resolve this typo mistake we just change large to Large.
Example 2:
Java
// Java Program to print largest numberpublic class Main { static int Large(int a, int b) { if (a > b) { return a; } else if (b > a) { return b; } else { return -1; } } public static void main(String... args) { // function call int value = Large(20, 4); System.out.println(value); }} |
20
Undeclared Variable
We can also get errors by undeclared Variables.
Example 1:
Java
// Java Program to demonstrate use of undeclared variablepublic class Main { public static void main(String[] args) { int n1 = 500; int n2 = 400; sum = n1 + n2; System.out.println(sum); }} |
Output:
./Main.java:6: error: cannot find symbol
sum = n1 + n2;
^
symbol: variable sum
location: class Main
./Main.java:7: error: cannot find symbol
System.out.println(sum);
^
symbol: variable sum
location: class Main
Explanation of the program
In the above example, the “Cannot find symbol” error occurs as we have not declared the sum. The corrected code is given below (will occur because “sum” is not declared. In order to solve the error, we need to define “int sum = n1+n2” before using the variable sum.
Example 2:
Java
// Java Program to pint sum of two numberspublic class Main { public static void main(String[] args) { int n1 = 500; int n2 = 400; int sum = n1 + n2; System.out.println(sum); }} |
900
Check the scope
Make sure that the symbol you are trying to reference is within the scope of the current code block.
Example 1:
Java
// Java Program to demonstrate scope of codepublic class Main { public static void main(String[] args) { int x = 5; if (x > 0) { int y = 10; } // error: cannot find symbol System.out.println(y); }} |
Output:
./Main.java:8: error: cannot find symbol
System.out.println(y);
^
symbol: variable y
location: class Main
Explanation of the above program
In this program, we define an integer variable x and initialize it to 5. We then have an if statement that checks if x is greater than 0. If it is, we define another integer variable y, and initialize it to 10. However, y is only within the scope of the if block, and cannot be accessed outside of it.
Example 2:
Java
public class Main { public static void main(String[] args) { int x = 5; int y = 0; if (x > 0) { y = 10; } System.out.println(y); }} |
10
Check the import statements
Make sure that any classes or packages that you are trying to reference are imported properly.
Example 1:
Java
// java program to demonstrate wrong use of import// statementsimport java.util.Rand; public class Main { public static void main(String[] args) { Rand rand = new Rand(); int x = rand.nextInt(10); System.out.println("Random number: " + x); }} |
Output:
./Main.java:1: error: cannot find symbol
import java.util.Rand;
^
symbol: class Rand
location: package java.util
./Main.java:6: error: cannot find symbol
Rand rand = new Rand();
^
symbol: class Rand
location: class Main
./Main.java:6: error: cannot find symbol
Rand rand = new Rand();
^
symbol: class Rand
location: class Main
Example 2:
Java
import java.util.Random; public class Main { public static void main(String[] args) { Random rand = new Random(); int x = rand.nextInt(10); System.out.println("Random number: " + x); }} |
Random number: 3
