Classpath for Compatible Versions of org.springframework.context.expression.standardbeanexpressionresolver and org.springframework.expression.spel.spelparserconfiguration

I recently encountered a technical issue that caused my Spring Boot application to fail during startup. The error message said something along the lines of:

"Correct the classpath of your application so that it contains compatible versions of the classes org.springframework.context.expression.standardbeanexpressionresolver and org.springframework.expression.spel.spelparserconfiguration."

This post is about my journey to resolve this classpath compatibility issue, what I learned, and some helpful solutions I found from various reputable sources.

Understanding the Classpath Compatibility Issue

When you see an error like this, it usually means there’s a version mismatch in your dependencies. Spring Boot relies on a specific set of compatible libraries, and when there’s an inconsistency—often due to a mix of different versions—conflicts arise.

In this case, org.springframework.context.expression.StandardBeanExpressionResolver and org.springframework.expression.spel.SpelParserConfiguration weren’t from compatible Spring versions, which caused the application to crash during runtime.

Step 1: Analyzing Dependencies

The first thing I did was check my project dependencies to see if any libraries were conflicting. Here’s a helpful way to view your dependencies in a Spring Boot application:

./gradlew dependencies

If you’re using Maven, you can use:

mvn dependency:tree

This allowed me to see the complete tree of dependencies, including any transitive dependencies that may be causing version conflicts.

Step 2: Identifying Conflicting Versions

As I reviewed the dependencies list, I noticed multiple versions of Spring-related jars. This can happen when a third-party library pulls in its own set of dependencies, leading to duplicate or incompatible versions of classes.

Look for duplicates of spring-context and spring-expression.
Note any non-compatible versions, especially if they’re older versions of Spring modules like spring-context or spring-expression.

Step 3: Exclude Conflicting Dependencies

When I identified the specific libraries causing the conflict, I needed to exclude the incompatible versions. Here’s how I handled it in my build.gradle file for Gradle:

dependencies {
implementation('org.springframework.boot:spring-boot-starter') {
exclude group: 'org.springframework', module: 'spring-expression'
}
implementation 'org.springframework:spring-expression:5.3.10'
}

In Maven, you would do something similar within the <dependencyManagement> section:

<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
<exclusions>
<exclusion>
<groupId>org.springframework</groupId>
<artifactId>spring-expression</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-expression</artifactId>
<version>5.3.10</version>
</dependency>
</dependencies>

This way, I forced the application to use a compatible version of spring-expression without interference from the older version.

Step 4: Aligning Dependencies with Spring Boot

BOM Spring Boot provides a Bill of Materials (BOM) that helps keep all dependencies aligned to compatible versions. I found that leveraging the Spring Boot BOM solved a lot of compatibility issues for me:

In Maven, add the BOM within the <dependencyManagement> section:

<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-dependencies</artifactId>
<version>2.5.5</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>

In Gradle, you can implement it like this:

dependencyManagement {
imports {
mavenBom "org.springframework.boot:spring-boot-dependencies:2.5.5"
}
}

Using the BOM simplifies things by automatically aligning Spring dependencies to compatible versions, which can prevent many compatibility issues.

Step 5: Additional Troubleshooting

After making these adjustments, I was still getting a similar error. This led me to try a few more options:Clearing the Cache: Sometimes, stale dependencies can cause issues, so I cleared the Gradle/Maven cache.

For Gradle: ./gradlew clean build --refresh-dependencies
For Maven: mvn clean install
Rebuild the Project: Often, a clean rebuild solves hidden issues.
Check for JDK Compatibility: Some versions of Spring libraries are sensitive to the JDK version. Make sure your JDK aligns with the Spring Boot version you’re using.

Step 6: Using Explicit Dependency Versions (Solution from GitHub Discussion)

While researching, I came across a suggestion in a GitHub discussion to specify explicit versions for Spring dependencies when encountering issues in projects with complex dependency graphs. For example:

dependencies {
implementation 'org.springframework:spring-context:5.3.10'
implementation 'org.springframework:spring-expression:5.3.10'
}

Setting specific versions for these libraries helped to avoid ambiguity, ensuring the application used only the intended versions of spring-context and spring-expression.

Solution-2

1. Dependency Management

Ensure that your project's dependencies are managed correctly. Use the Spring Boot Starter Parent or Spring Dependency Management to maintain consistent versions.

pom.xml (Maven)
XML
<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-parent</artifactId>
            <version>2.7.3</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

build.gradle (Gradle)
Groovy
dependencies {
    implementation 'org.springframework.boot:spring-boot-starter:2.7.3'
}

2. Exclude Transitive Dependencies

Exclude transitive dependencies that may cause conflicts.

pom.xml (Maven)
XML
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-expression</artifactId>
    <version>5.3.23</version>
    <exclusions>
        <exclusion>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
        </exclusion>
    </exclusions>
</dependency>

build.gradle (Gradle)

Groovy
dependencies {
    implementation('org.springframework:spring-expression:5.3.23') {
        exclude group: 'org.springframework', module: 'spring-core'
    }
}

3. Force Compatible Versions Force compatible versions of conflicting dependencies.

pom.xml (Maven)
XML
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-context</artifactId>
    <version>5.3.23</version>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-expression</artifactId>
    <version>5.3.23</version>
</dependency>
build.gradle (Gradle)
Groovy
dependencies {
    implementation 'org.springframework:spring-context:5.3.23'
    implementation 'org.springframework:spring-expression:5.3.23'
}

Resolving classpath issues with Spring Framework requires careful dependency management. By following these solutions, you should be able to correct the classpath of your application and ensure compatible versions of StandardBeanExpressionResolver and SpelParserConfiguration.