How to resolve class path resource cannot be opened because it does not exist exception when trying to read file from classpath with java

Feb 5, 2025

Purpose

In this post, I will demonstrate how to resolve the class path resource cannot be opened because it does not exist problem when using Java to load a file from the classpath.

The directory structure is as follows:

➜  test git:(master) ✗ tree -N
.
├── java
│   └── com
│       └── abc
│           └── tweb
│               └── service
│                   └── impls
│                       └── TestDefaultSourceParser.java
└── testfiles
    └── test1.txt

8 directories, 2 files

The code we are using to load the test1.txt is as follows:

package com.abc.tweb.service.impls;

import lombok.extern.slf4j.Slf4j;
import org.apache.commons.io.IOUtils;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.core.io.ClassPathResource;
import org.springframework.test.context.junit4.SpringRunner;

import java.io.InputStream;

import static org.junit.Assert.assertTrue;

@RunWith(SpringRunner.class)
@SpringBootTest
@Slf4j
public class TestDefaultSourceParser {
    @Autowired
    private DefaultSourceParser sourceParser;

    @Test
    public void test1() throws Exception {
        try (InputStream stream = new ClassPathResource("/testfiles/test1.txt").getInputStream()) {
            String source = IOUtils.toString(stream);
            log.debug("source:" + source);
            assertTrue(source != null && source.length() > 0);
        }
    }
}

Environment

Spring Boot 2+
Java 8+

The Solution

We should place the file in the correct location:

➜  tweb git:(master) ✗ tree -N .
.
├── java
│   └── com
│       └── abc
│           └── tweb
│               └── service
│                   └── impls
│                       └── TestDefaultSourceParser.java
└── resources
    └── testfiles
        └── test1.txt

8 directories, 2 files

As you can see, the file testfiles/test1.txt should be placed in the ./resources directory, either src/main/resources or src/test/resources.

Then run the following code:

package com.abc.tweb.service.impls;

import lombok.extern.slf4j.Slf4j;
import org.apache.commons.io.IOUtils;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.core.io.ClassPathResource;
import org.springframework.test.context.junit4.SpringRunner;

import java.io.InputStream;

import static org.junit.Assert.assertTrue;

@RunWith(SpringRunner.class)
@SpringBootTest
@Slf4j
public class TestDefaultSourceParser {
    @Autowired
    private DefaultSourceParser sourceParser;

    @Test
    public void test1() throws Exception {
        try (InputStream stream = new ClassPathResource("/testfiles/test1.txt").getInputStream()) {
            String source = IOUtils.toString(stream);
            log.debug("source:" + source);
            assertTrue(source != null && source.length() > 0);
        }
    }
}

We get this result:

source: xxxxx
Test success.

Why Did This Work?

As shown in the code, we are using ClassPathResource to load the resource file from the classpath. Let’s look at the details of this class:

public class ClassPathResource extends AbstractFileResolvingResource

Resource implementation for class path resources. Uses either a given ClassLoader or a given Class for loading resources.

Supports resolution as java.io.File if the class path resource resides in the file system, but not for resources in a JAR. Always supports resolution as URL.

So the leading slash is not required, so the following line would work too:

InputStream stream = new ClassPathResource("testfiles/test1.txt").getInputStream()

Summary

In this post, I demonstrated how to resolve the FileNotFoundException when using Java to load a file from the classpath. The key point is to place the file in the correct directory. By ensuring the file is in the resources directory and using the correct path in the code, you can successfully load the file.

Final Words + More Resources

My intention with this article was to help others who might be considering solving such a problem. So I hope that’s been the case here. If you still have any questions, don’t hesitate to ask me by email: Email me

Here are also the most important links from this article along with some further resources that will help you in this scope:

👨‍💻 Spring Boot and Java

Oh, and if you found these resources useful, don’t forget to support me by starring the repo on GitHub!