What Does a Cannot find symbol or Cannot resolve symbol Error Mean?

While working with Java, we might get the error “Cannot find symbol”. This is a compiler error that may occur when the Java compiler cannot recognize a variable, method, class, or reference in the code. Java provides multiple approaches by which we can fix these types of errors.

In this blog, we will explore why the ‘Cannot Find Symbol’ error occurs, provide examples, and discuss ways to fix it

Table of Contents:

• What Causes the Java Cannot Find Symbol Error?
• Examples of Java Cannot Find Symbol error
  • Example 1: Using an Undeclared Variable
  • Example 2: Variable or Method is Out of Scope
  • Example 3: Misspelled Variable, Method, or Class Name
  • Example 4: Missing Import Statement for External Classes
• How to Fix the Error “Cannot Find Symbol”?
• Cannot Find Symbol vs Symbol Not Found vs Cannot Resolve Symbol
• Conclusion

What Causes the Java Cannot Find Symbol Error?

In Java, Cannot Find Symbol is a compile-time error that occurs due to the following reasons:

• When you use an undeclared variable or method,
• When you use any variable or method outside the defined scope,
• When we misspelled a variable or method,
• When we use incorrect import and export statements,
• When we are using a method or variable declared outside the package

Examples of Java Cannot Find Symbol error

Let’s learn how this error will occur through some examples:

Example 1: Using an Undeclared Variable

If a variable is used before being declared, the compiler cannot recognize it, and throws an error.

Example Code:

Output:

Explanation: In the above code, we are trying to print the value of number, but we haven’t declared it yet in the Program.

Example 2: Variable or Method is Out of Scope

If a variable is declared inside a block (such as inside a method or loop) and accessed outside, Java will not recognize it.

Example Code:

Output:

Explanation: In the above code, we have defined the value of x inside an if-block, but trying to access it from outside the current block, that will throw us an error.

Example 3: Misspelled Variable, Method, or Class Name

Java is a case-sensitive language, which means it treats uppercase and lowercase letters differently. Incorrect spelling will lead to this error.

Example Code:

Output:

Explanation: In the above code, we have declared the method named printMessage(), but calling the method named printMsg(), which is wrong spelling of the original method, that’s why we get this error.

Example 4: Missing Import Statement for External Classes

If a class from another package is used without an import statement, the compiler will not recognize it, and throws an error.

Example Code:

Output:

Explanation: In the above code, we are trying to declare an ArrayList, but we haven’t imported the package of ArrayList.

To fix the above code, we have to use the below import statements at the top of the Java file:

import java.util.List;
import java.util.ArrayList;'

How to Fix the Error “Cannot Find Symbol”?

You can fix the error ‘Cannot Find Symbol’ with the following best practices:

• Check for Typos: Before running the program, you have to check the variable, method, and class names are spelled correctly or not.
• Verify Scope: You have to check the variable or method is declared within the correct scope and is accessible where it is being used.
• Import Required Classes: If you are using a class from another package, you must import that package into the current file.
• Declare Variables Before Use: Always declare a variable before referencing it in your code.
• Check for Case Sensitivity: Java is case-sensitive, so make sure that identifiers match exactly as declared.
• Compile All Files: If you are working with multiple files, make sure dependent classes are compiled properly before execution.
• Fix Constructor and Method Calls: You have to verify that method and constructor calls use the correct parameters and match the expected signatures.

Cannot Find Symbol vs Symbol Not Found vs Cannot Resolve Symbol

Here are the key differences between the errors: ‘Cannot Find Symbol,’ ‘Symbol Not Found,’ and ‘Cannot Resolve Symbol’.

Conclusion

So far in this blog, we have learned the reasons behind the error “Cannot Find Symbol”, how we can fix it with some best practices. By carefully checking for typos, using proper variable scope, and managing imports and exports correctly, we can avoid this error.

If you want to master all the concepts of Java language, you may refer to our Java course.

Cannot find symbol or Cannot resolve symbol Error – FAQs