Maven is a powerful project management tool that developers use for building and managing any Java-based project. However, like any other tool, it can sometimes throw errors that might seem daunting at first. One such error is “Unable to load cache item”. This error is often related to a version compatibility problem between Maven and Java. In this article, we will focus on how to fix this error when using Ubuntu 20.04.2 LTS with Java 17.
To fix the Maven error "Unable to load cache item" on Ubuntu 20.04.2 LTS with Java 17, you have two options. The first option is to update Maven to a version that is compatible with Java 17, such as Maven 3.8.6. The second option is to specify a lower Java version in the Maven configuration, such as Java 16.
Understanding the Error
The error message “Unable to load cache item” suggests that Maven is unable to load a cache item due to an issue with the class com.google.inject.internal.cglib.core.$MethodWrapper. This problem seems to stem from the version compatibility between Maven and Java. For instance, if you’re using Maven 3.6.3 with Java 17, you might face this error because Maven 3.6.3 is not fully compatible with Java 17.
Solution 1: Update Maven
One of the easiest ways to fix this error is to update Maven to a version that is compatible with Java 17. As of the time of writing, Maven 3.8.6 is the latest version and it is compatible with Java 17. Here are the steps to manually install Maven 3.8.6:
- Download Maven 3.8.6: You can download it from the Apache Maven website. Choose the binary tar.gz archive.
- Extract the archive: Use the
tarcommand to extract the archive. The-xzfparameter is used to extract files from agzarchive.
tar -xzf apache-maven-3.8.6-bin.tar.gz- Move the extracted directory: Move the extracted directory to
/opt/directory.
sudo mv apache-maven-3.8.6 /opt/maven- Set up environment variables: Set up
M2_HOME,JAVA_HOME, andPATHenvironment variables.
echo "export M2_HOME=/opt/maven" >> ~/.bashrc
echo "export JAVA_HOME=/usr/lib/jvm/java-17-openjdk-amd64" >> ~/.bashrc
echo "export PATH=${M2_HOME}/bin:${PATH}" >> ~/.bashrc
source ~/.bashrc- Verify the installation: Verify the installation by checking the Maven version.
mvn -versionIf the installation is successful, this command will output the version of Maven that you just installed.
Solution 2: Specify a Lower Java Version
If updating Maven is not an option, another solution is to specify a lower Java version in the Maven configuration. Here’s how you can do it:
- Install a lower version of Java: Install Java 16 or lower using the
aptpackage manager.
sudo apt install openjdk-16-jdk- Create a
~/.mavenrcfile: This file allows you to specify environment variables for Maven.
nano ~/.mavenrc- Set the
JAVA_HOMEenvironment variable: In the~/.mavenrcfile, set theJAVA_HOMEenvironment variable to the path of the lower Java version.
export JAVA_HOME=/usr/lib/jvm/java-16-openjdk-amd64- Save and close the file: Press
Ctrl + X, thenY, and finallyEnterto save and close the file. - Verify the configuration: Run a Maven command to verify that the configuration works.
mvn -versionIf the configuration is successful, this command will output the version of Maven and the version of Java it is using.
In conclusion, the “Unable to load cache item” error in Maven on Ubuntu 20.04.2 LTS with Java 17 can be fixed by either updating Maven to a version that is compatible with Java 17 or specifying a lower Java version in the Maven configuration. Both solutions are effective, so choose the one that best fits your situation.
Maven is a project management tool used primarily for building and managing Java-based projects. It helps in automating the process of project dependency management, compilation, testing, and packaging.
Maven works based on a declarative XML file called a "pom.xml" (Project Object Model). This file contains project information, dependencies, plugins, and build configurations. Maven uses the information in the pom.xml to download dependencies, compile source code, run tests, and create artifacts like JAR or WAR files.
You can check the version of Maven installed on your system by running the following command in the terminal:
mvn -versionThis will display the Maven version along with other information like Java version and Maven home directory.
To update Maven to the latest version, you can follow the steps mentioned in Solution 1 of the article. Download the latest version of Maven from the Apache Maven website and install it manually. Make sure to update the environment variables accordingly.
Yes, you can specify a lower version of Java in the Maven configuration. Follow the steps mentioned in Solution 2 of the article to set the JAVA_HOME environment variable to the path of the lower Java version. Maven will then use the specified Java version for the project.
While version compatibility between Maven and Java is a common cause of this error, there can be other causes as well. It could be due to a corrupt Maven cache or a conflict with other dependencies. However, in the context of this article, we have focused on the version compatibility issue as the main cause of the error.
