How to debug NoSuchMethodError exception?

Question

I am running the following code

package test.commons;

import java.io.File;
import java.io.IOException;

import org.apache.commons.io.FileUtils;

public class Try_FileUtilsWrite {

    public static void main(String[] args) throws IOException {
        System.out.println(FileUtils.class.getClassLoader());
        FileUtils.write(new File("output.txt"), "Hello world");
    }

}

and getting

Exception in thread "main" java.lang.NoSuchMethodError: org.apache.commons.io.FileUtils.write(Ljava/io/File;Ljava/lang/CharSequence;)V
    at test.commons.Try_FileUtilsWrite.main(Try_FileUtilsWrite.java:12)

apparently, an old version of commons io used somewhere. But I don't see it in the project.

Is it possible to know the path to class file at runtime?

How are you running it? Show us the full `java` command. – Sotirios Delimanolis Apr 06 '15 at 15:43 — Sotirios Delimanolis, Apr 06 '15 at 15:43
can you show a list of the dependencies? – EpicPandaForce Apr 06 '15 at 15:44 — EpicPandaForce, Apr 06 '15 at 15:44

score 10 · Accepted Answer · answered Apr 06 '15 at 15:47

10

Yes you can use that Classloader to get the resource from which the class is loaded:

ClassLoader classLoader = FileUtils.class.getClassLoader();

URL resource = classLoader.getResource("org/apache/commons/io/FileUtils.class");
System.out.println(resource);

Sample output:

jar:file:/D:/maven_repository/commons-io/commons-io/2.0.1/commons-io-2.0.1.jar!/org/apache/commons/io/FileUtils.class

answered Apr 06 '15 at 15:47

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Thanks for this. In my case, turned out I needed to run `mvn clean` on a maven module I wasn't expecting to have to clean. – Muhd Aug 12 '16 at 21:56

How to debug NoSuchMethodError exception?

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