In this article, we’ll see the reason behind the error can not find symbol or can not resolve symbol in Java So you can solve it by removing that cause. So let’s start.
A java program consists of keywords, literals, operators, comments, whitespaces, and identifiers. This error is related to identifiers (an identifier is a name that user assign to an element of a program such as a type, function, variable, namespace, or class). Because when you compile your code, the compiler needs to know about each of the identifiers that we have used, and when we put an identifier that refers to something, and the compiler doesn’t understand that so it throws the error “can not find symbol”.
Reason 1: Using an Undeclared Variable
Example:
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public class Demo { public static void main(String[] s) { int n1 = 10; int n2 = 20; sum = n1+n2; System.out.println("Sum = "+ sum); } } |
Output:
Demo.java:8: error: cannot find symbol
sum = n1+n2;
^
symbol: variable sum
location: class Demo
In the above program, we are using the sum variable to store the sum of n1 and n2 variables and our program is throwing the error “cannot find symbol” and it is pointing to the sum variable. So we can easily solve it by declaring the sum variable before using it.
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int sum; sum = n1+n2; |
So make sure your code won’t be having this mistake.
Reason 2: Spelling Mistakes or Using Wrong Cases
Example:
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public class Demo { public static void main(String[] s) { int n1 = 10; int n2 = 20; int sum; sum = n1+n2; System.out.println("Sum= "+ Sum); } } |
Output:
Demo.java:10: error: cannot find symbol
System.out.println(“Sum= “+ Sum);
^
symbol: variable Sum
location: class Demo
Again this is one of the most common reasons for this error. Java is a case sensitive language which means Sum is different from the sum. So we have to use the exact name in the same case format as we have declared it to prevent this error.
Reason 3: Variable is Out of Scope
Example:
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public class Demo { public static void main(String[] s) { for(int i = 0; i<=10; i++) { System.out.println("i =" + i); } System.out.println("loop breaked at - " + i); } } |
Output:
Demo.java:11: error: cannot find symbol
System.out.println(“loop breaked at – ” + i);
^
symbol: variable i
location: class Demo
1 error
So here we can see that even we have declared the variable i and still it is showing “cannot symbol error” because we have declared it inside for loop and trying to use it outside of for loop. It’s called out of scope. To prevent this make sure that your variable is defined in the same scope where you’re using it. Like in the above program to use i outside of the for loop i have declared i inside the main function.
Reason 4: Forgot to Import Class
Example:
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public class Demo { public static void main(String[] s) { ArrayList a = new ArrayList(); } } |
Output:
error: cannot find symbol
ArrayList a = new ArrayList();
^
symbol: class ArrayList
location: class Demo
Here, we are using the correct spelling of ArrayList to use it. But still, it says “cannot find symbol”. Again compiler couldn’t find the meaning of the ArrayList because ArrayList exists in a package “java.util”, so to use it we have to import ArrayList from this package. It is again a common mistake we usually do by using a class or method without importing it in our program. If you’re using an editor like visual studio code or eclipse you can fix it by hovering on the ArrayList and it will show the package to import. But if you’re using a simple text editor then you have to manually write a line at the top of your java file.
import java.util.ArrayList;
So make sure for the next time, you’ve imported all the classes that you’re using in your program.
Reason 5: Using a Method that is Undefined for the Class
Example:
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import java.util.ArrayList; public class Demo { public static void main(String[] s) { String string = "the crazy programmer"; System.out.println(s.size()); } } |
Output:
Demo.java:8: error: cannot find symbol
System.out.println(s.size());
^
symbol: method size()
location: variable s of type String[]
1 error
Here is another example that cause the same error. Here i am trying to get the size or length of the string using size() method which is not a String class’s method. It is used to get the size of an array, not the string that’s why it is showing this error. So make sure that the methods we’re using are defined for the class or not. In the above case the right we can use length property instead of size() method to get the size of a string.
So these were some reasons when we face cannot find symbol error. I hope this article has helped you to solve this. If you have any queries or suggestions related to this article please comment below.
