Initializer has been compiled by a more recent version of the Java Runtime (class file version 61.0)

indicates that the class RefreshBootstrapRegistryInitializer has been compiled with a Java version 17 (which corresponds to class file version 61.0), but you're attempting to run it on an older Java version (likely Java 8, which corresponds to class file version 52.0).

Solution:

You have two options to resolve this:

Option 1: Upgrade Your Java Version to 17 or Later

Since the class you're trying to use (RefreshBootstrapRegistryInitializer) was compiled with Java 17 (class version 61.0), you'll need to upgrade your Java Runtime Environment (JRE) to Java 17 or later. This is the recommended approach if you want to work with newer dependencies that require a higher Java version.

1. Install Java 17 (or later):

   • On macOS:

     brew install openjdk@17

   • On Ubuntu/Debian

     sudo apt install openjdk-17-jdk

   • On Windows: Download the installer from the official OpenJDK 17 website or from AdoptOpenJDK.

2. Set Java 17 as your default version:

   Ensure that your JAVA_HOME environment variable points to Java 17:

   • On Linux/macOS:

     export JAVA_HOME=/path/to/java-17 export PATH=$JAVA_HOME/bin:$PATH

   • On Windows: Set the JAVA_HOME system environment variable to the path where Java 17 is installed.

3. Rebuild your project with Java 17.

Option 2: Compile for Java 8 (class version 52.0)

If you can't upgrade to Java 17 and must stay with Java 8 (which corresponds to class file version 52.0), you'll need to ensure that all your dependencies, including Spring Cloud and any libraries, are compatible with Java 8.

To do this, you can configure your Maven or Gradle build to target Java 8 while still compiling with Java 8.

Here’s how you can configure it:

For Maven:

1. Ensure that your pom.xml file includes the correct configuration for Java 8:

   <properties> <maven.compiler.source>1.8</maven.compiler.source> <maven.compiler.target>1.8</maven.compiler.target> </properties>

2. Make sure all dependencies (like spring-cloud-context) are compatible with Java 8, or downgrade to a version that supports Java 8 (like Spring Cloud 2020.x or earlier).

For Gradle:

1. Add the following to your build.gradle file:

   java { sourceCompatibility = JavaVersion.VERSION_1_8 targetCompatibility = JavaVersion.VERSION_1_8 }

2. Verify that your dependencies are compatible with Java 8 (such as Spring Cloud 2020.x).

Option 3: Downgrade Your Dependencies to Versions Compatible with Java 8

If upgrading to Java 17 is not an option, the best approach is to downgrade your dependencies to versions that are compatible with Java 8. Specifically:

• Ensure you are using versions of Spring Cloud that are compatible with Java 8 (for Spring Cloud, that would generally be 2020.x or earlier).
• Review the dependency versions in your pom.xml or build.gradle to make sure they are compatible with Java 8.

Example of Spring Cloud dependency for Java 8:

<dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-context</artifactId> <version>2020.0.3</version> <!-- Use Spring Cloud 2020.x or earlier for Java 8 compatibility --> </dependency>

Conclusion:

• Upgrade to Java 17 or later if possible, as this will allow you to use the newer dependencies compiled for Java 17.
• If you're required to stay with Java 8, ensure all your dependencies are compatible with Java 8 by downgrading them, especially Spring Cloud to a 2020.x version.