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Updated on 2025-04-11

Quickly solve the IDEA error: "java cannot find symbol" ("cannot find symbol")

In useIntelliJ IDEAWhen developing a Java project, you may encounter error messages similar to the following:

error: cannot find symbol
  symbol:   class MyClass
  location: package mypackage

Or other similar prompts: "Symbol not found". This error is usually due toThe compiler cannot recognize or locate certain classes, methods, variables, etc.Caused by. There may be a variety of specific reasons. The following will explain in detail how to analyze and solve the problem, and help understand it through specific code examples.

1. Common causes of “cannot find symbol” errors

Missing import statement

  • If an external class or package is used, but no relevant package or class is imported, an error of "Symbol Not Found" will occur.

Error spelling

  • Misspelling of the name of a variable, class, or method can cause the compiler to fail to find the symbol.

Classpath issue

  • When the classpath or build path (classpath) in the project is not set correctly, the compiler will not be able to find the required class.

Uncompiled files

  • The code file is not compiled, or the compiled bytecode is not updated, which may cause the symbol to be found.

Version issues

  • Incompatible Java or JDK versions were used, resulting in the symbol being unable to be found at compile time.

IDE configuration issues

  • The project settings in the IDE may cause the IDE to not recognize the symbol.

2. Solution

1. Check the import statement

If an external class or library is used, make sure it has been imported correctly. For example, we have oneMyClassClass inmypackageIn the package, but the class is not imported in the current file.

Error code:

public class Main {
    public static void main(String[] args) {
        MyClass obj = new MyClass();  // An error will be reported here: cannot find symbol    }
}

Solution:
Need to importMyClassPackage:

import ;
public class Main {
    public static void main(String[] args) {
        MyClass obj = new MyClass();  // Normal operation    }
}

2. Check for spelling errors

In Java, the names of variables, classes, and methods are case sensitive. If the spelling is wrong, it will also lead to an error of "Symbol Not Found".

Error code:

public class Main {
    public static void main(String[] args) {
        String name = "Java";
        (Name);  // An error will be reported here: cannot find symbol    }
}

Solution:

public class Main {
    public static void main(String[] args) {
        String name = "Java";
        (name);  // Normal operation    }
}

3. Check the classpath settings

If there are external dependencies in the project, make sure the project's classpath is set correctly. If it is a Maven or Gradle project, checkorWhether the correct dependency is included.

Error code:

Assume that the project is usedJacksonlibrary, butJacksonThe dependency of the dependent is not added, and the runtime will report "Symbol Not Found".

public class Main {
    public static void main(String[] args) {
        ObjectMapper objectMapper = new ObjectMapper();  // An error will be reported here: cannot find symbol    }
}

Solution:
Add the correct Maven dependency:

<dependency>
    <groupId></groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.13.0</version>
</dependency>

Or, use Gradle:

implementation ':jackson-databind:2.13.0'

4. Make sure the file is compiled correctly

Sometimes IDEA does not automatically compile the file, or the compiled bytecode is not updated. Try recompiling the entire project manually.

Solution:

  • Rebuilding project: ClickBuild > Rebuild ProjectRecompile.
  • Clean the cache and restart: If the recompilation is invalid, you can try to clean the cache and restart the IDE. ClickFile > Invalidate Caches / Restart。

5. Check JDK configuration

Confirm that your project is using the correct JDK version. If your project uses the JDK 8 feature and your IDE or build tool is configured with a lower version of the JDK, it will result in unrecognized errors.

Solution:
existIntelliJ IDEAmiddle:

  • Open Project Settings:File > Project Structure。
  • existProjectUnder the tag, make sure that the correct JDK version is selected.
  • existModules, make sure that the JDK version of your module is used correctly.

6. IDE configuration issues

If you are sure there is no problem with the code itself, it may be an IDEA configuration problem. Try reloading the Maven project or Gradle project.

Solution:

  • For Maven project, right-click on the project and selectMaven > Reload Project。
  • For Gradle projects, right-click on the project and selectGradle > Refresh Gradle Project。

3. Sample code: From error to solution

Suppose we have the following code, using oneMathUtilsClass, but there is an error "Symbol Not Found":

3.1 Error code: Symbol not found

public class Main {
    public static void main(String[] args) {
        int result = (10, 20);  // Symbol not found        ("Result: " + result);
    }
}

error message:

error: cannot find symbol
  symbol:   class MathUtils
  location: class Main

3.2 Solution 1: Add the correct class

make sureMathUtilsThe class is defined and located in the correct package. ifMathUtilsClass inutilsPackage:

package utils;
public class MathUtils {
    public static int add(int a, int b) {
        return a + b;
    }
}

existMainCorrect import in classMathUtils：

import ;
public class Main {
    public static void main(String[] args) {
        int result = (10, 20);  // Normal operation        ("Result: " + result);
    }
}

3.3 Solution 2: Make sure the file is compiled

If the error still appears, try cleaning and rebuilding the project:

  • ClickBuild > Rebuild Project。
  • If the problem remains the same, chooseInvalidate Caches / Restart。

3.4 Solution 3: Check JDK Configuration

Make sure the project is using the correct JDK version. Assuming that the project requires JDK 8, and the currently configured JDK version is lower, it may throw a similar error. passProject StructureConfigure the JDK version.

4. Summary

"Symbol not found" (cannot find symbol) Errors are one of the common compilation errors in Java programming, and are usually caused by the following reasons:

  • The import statement is missing.
  • Miss spelling.
  • Classpath issue.
  • Uncompiled file.
  • IDE configuration issues.

This error is usually resolved smoothly by carefully examining the code, import statements, classpaths, and IDE settings. I hope the summary of this article can help you troubleshoot and resolve the "Symbol Not Found" error in the IDE.

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