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The New Version Java command extracts a Java tar archive and registers it with the system’s alternatives system, making it available for use alongside other Java versions.

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When to use this command

Use this command when you:
  • Have downloaded a new Java JDK tar file (e.g., jdk-21.tar.gz)
  • Want to add another Java version to your system
  • Need to install a specific Java version for project requirements

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Prerequisites

Before running this command, ensure:
  • You have a Java tar file downloaded
  • The /opt/java directory exists on your system
  • You have sudo privileges

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Step-by-step usage

1

Select the command

From the interactive menu, choose “New Version Java”
2

Enter tar file name

When prompted, enter the name of your Java tar file:
Enter the name of the tar file
jdk-21.tar.gz
The tar file should be in your current directory.
3

Tar extraction

The tool automatically extracts the tar file and moves it to /opt/java/:
Tar decompress correctly
You’ll then see a list of all Java folders in /opt/java.
4

Specify folder name

Enter the folder name for your new Java version:
Ej. jdk-21
Enter the folder for the new Java version
jdk-21
This is the directory name inside /opt/java/ where your Java installation resides.
5

Set version priority

Assign a priority number to your Java version:
Ej. Java 21 === 2100
Enter the Java version
2100
Higher numbers = higher priority. The system will use the highest priority version when set to auto mode.
6

Installation complete

The tool registers all three Java binaries:
Java installed
Your new Java version is now available in the system.

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What happens behind the scenes

The command performs several operations as shown in internal/commands/newjava.go:13-78:

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1. Directory verification

info, err := os.Stat("/opt/java")
helps.ExistDir(info, err)
Verifies that /opt/java exists, creating it if necessary.

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2. Tar extraction and move

helps.ExtracFile(tar)
maches := helps.ExtractNameDir()
pathF := "/opt/java/" + maches[0]
err = u.RunCommandInteractive("sudo", "mv", maches[0], pathF)
Extracts the tar file and moves it to the Java directory.

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3. Register with update-alternatives

For each binary (java, javac, jar), the tool runs: 
java := pathR + "/java"
javac := pathR + "/javac"
jar := pathR + "/jar"

err = u.RunCommandInteractive("sudo", "update-alternatives", "--install", "/usr/bin/java", "java", java, version)
err = u.RunCommandInteractive("sudo", "update-alternatives", "--install", "/usr/bin/javac", "javac", javac, version)
err = u.RunCommandInteractive("sudo", "update-alternatives", "--install", "/usr/bin/jar", "jar", jar, version)
These commands register the binaries with Linux’s alternatives system.

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Real terminal example

$ javaoptionscli
# Select "New Version Java" from menu

Enter the name of the tar file
jdk-17.0.9.tar.gz
Tar decompress correctly
Here are your Java versions and their folders
drwxr-xr-x  - root 12 Jan 10:30 jdk-11
drwxr-xr-x  - root 12 Jan 10:31 jdk-17

Ej. jdk-21
Enter the folder for the new Java version
jdk-17

Ej. Java 21 === 2100
Enter the Java version
1700

Java installed

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Common use cases

If you maintain projects requiring different Java versions, install each version with appropriate priority:
  • Java 8: priority 800
  • Java 11: priority 1100
  • Java 17: priority 1700
  • Java 21: priority 2100
When a new Java version is released, you can install it alongside existing versions without affecting your current setup. Give it a lower priority initially for testing.
You can install both Oracle JDK and OpenJDK versions side by side, using different folder names like jdk-17-oracle and jdk-17-openjdk.
The priority number is permanent for this installation. To change priority later, you’ll need to delete and reinstall the version.

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Troubleshooting

Error: Directory /opt/java doesn’t exist
  • Create it with: sudo mkdir -p /opt/java
Error: Permission denied
  • Ensure you have sudo privileges
  • The command will prompt for your password when needed
Tar extraction fails
  • Verify the tar file is in your current directory
  • Check the tar file isn’t corrupted: tar -tzf your-file.tar.gz

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