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Intranet-Only Projects Pitfall (Maven and SVN)

#webdev #programming #java #maven

Recently, I had my very first experience working on a project that runs completely offline on an intranet. Since I had to figure out a lot of things from scratch, I decided to write down the issues I ran into — hopefully this saves someone else a few hours of frustration!

🛠 Maven Offline Mode Gotcha

Because of intranet security requirements, the project runs on a virtual machine that cannot access the Internet. This means we need to have all dependencies pre-downloaded and available locally.

While configuring pom.xml, IntelliJ IDEA kept throwing a strange error:

Cannot access maven-default-http-blocker (http://0.0.0.0/) in offline mode

At first, I tried enabling Maven's offline mode, as most blog posts suggested — but that didn’t help at all. After some digging, I realized it was actually a Maven version issue.

The version of Maven bundled with my IDEA (Maven 3.8+) includes the following configuration in settings.xml by default:

<mirror>
  <id>maven-default-http-blocker</id>
  <mirrorOf>external:http:*</mirrorOf>
  <name>Pseudo repository to mirror external repositories initially using HTTP.</name>
  <url>http://0.0.0.0/</url>
  <blocked>true</blocked>
</mirror>
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This is Maven’s way of blocking external HTTP repositories for security reasons — to prevent man-in-the-middle attacks when downloading dependencies.

🔧 Solution

You have two main options:

  1. Downgrade Maven to a version prior to 3.8, which doesn’t block HTTP by default.
  2. If you want to keep using the bundled Maven, edit the settings.xml under \plugins\maven\lib\maven3\conf (inside your IDEA installation directory) and comment out the maven-default-http-blocker mirror.

Personally, I went with option 2. Just be aware that this weakens security since HTTP downloads are no longer blocked — make sure you trust your intranet repository.

📥 Importing Projects from SVN in IDEA

To make things more interesting, this project uses SVN instead of Git. Importing it into IntelliJ IDEA was straightforward but had one unexpected issue.

Like with Git, you can go to File → New → Project from Version Control, and then select Subversion (SVN) from the dropdown menu:

project pitfall 1

After entering the company’s SVN repository URL, IDEA will automatically fetch the project folders (source, tests, packages, etc.).

But… I hit another error:

Cannot run program “svn”: CreateProcess error=2

Turns out this happens because IDEA relies on the SVN command-line client, and if it isn’t installed locally, it just fails.

🔧 Solution

Re-run the SVN installer (.msi file), choose Modify, and make sure to install the Command Line Client Tools option:

project pitfall 2

After that, everything worked smoothly.

💡 Takeaways

  • Check Maven version early if you’re working in an offline environment — 3.8+ blocks HTTP repos by default.
  • Don’t forget the CLI tools when using SVN with IDEA — GUI integration depends on them.
  • Working in an intranet-only setup requires a bit more preparation, but once things are configured, development feels the same as online.

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