How to solve the error: "java.net.UnknownHostException: username:[email protected]:port"

[kuanyan9527]

I get an error when run command graalpy -m standalone native --module test.py --output test --venv venv

Error message:
INFO: downloading org.graalvm.python:python-embedding:24.2.1 from https://repo1.maven.org/maven2/ to graalpy-24.2.1-linux-amd64/downloaded_standalone_resources May 29, 2025 4:25:49 PM org.graalvm.maven.downloader.MVNDownloader getProxy INFO: using proxy 'http://username:[email protected]:port' May 29, 2025 4:25:49 PM org.graalvm.maven.downloader.MVNDownloader downloadMavenFile SEVERE: exception while downloading maven file from https://repo1.maven.org/maven2/org/graalvm/python/python-embedding/24.2.1/python-embedding-24.2.1.pom java.net.UnknownHostException: username:[email protected]:port at [email protected]/sun.nio.ch.NioSocketImpl.connect(NioSocketImpl.java:558) at [email protected]/java.net.Socket.connect(Socket.java:665) at [email protected]/java.net.Socket.connect(Socket.java:603) at [email protected]/sun.net.NetworkClient.doConnect(NetworkClient.java:166) at [email protected]/sun.net.www.http.HttpClient.openServer(HttpClient.java:516) at [email protected]/sun.net.www.http.HttpClient.openServer(HttpClient.java:570) at [email protected]/sun.net.www.http.HttpClient.openServer(HttpClient.java:599) at [email protected]/sun.net.www.protocol.https.HttpsClient.<init>(HttpsClient.java:205) at [email protected]/sun.net.www.protocol.https.HttpsClient.New(HttpsClient.java:287) at [email protected]/sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.getNewHttpClient(AbstractDelegateHttpsURLConnection.java:193) at [email protected]/sun.net.www.protocol.http.HttpURLConnection.plainConnect0(HttpURLConnection.java:1007) at [email protected]/sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:898) at [email protected]/sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(AbstractDelegateHttpsURLConnection.java:179) at [email protected]/sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1376) at [email protected]/sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1301) at [email protected]/java.net.HttpURLConnection.getResponseCode(HttpURLConnection.java:493) at [email protected]/sun.net.www.protocol.https.HttpsURLConnectionImpl.getResponseCode(HttpsURLConnectionImpl.java:307) at org.graalvm.maven.downloader.MVNDownloader.downloadFromServer(MVNDownloader.java:220) at org.graalvm.maven.downloader.MVNDownloader.downloadMavenFile(MVNDownloader.java:200) at org.graalvm.maven.downloader.MVNDownloader.downloadDependencies(MVNDownloader.java:109) at org.graalvm.maven.downloader.Main.main(Main.java:163) at com.oracle.graal.python.shell.GraalPythonMain.polyglotGet(GraalPythonMain.java:156) at com.oracle.graal.python.shell.GraalPythonMain.preprocessArguments(GraalPythonMain.java:167) at org.graalvm.launcher.AbstractLanguageLauncher.launch(AbstractLanguageLauncher.java:282) at org.graalvm.launcher.AbstractLanguageLauncher.launch(AbstractLanguageLauncher.java:126) at org.graalvm.launcher.AbstractLanguageLauncher.runLauncher(AbstractLanguageLauncher.java:180)
I have to connect to the Internet through a proxy，but I'm not sure if this is caused by the proxy.
According to the prompt information, I want to solve it by changing the internal mvn source. When I checked the org.graalvm.maven.downloader source code, I found a way to set the source, but I cant not set "org.graalvm.maven.downloader.repository" environment.

...
static final String DEFAULT_MAVEN_REPO = "https://repo1.maven.org/maven2/";
static final String MAVEN_PROP = "org.graalvm.maven.downloader.repository";
...

public static String getDefaultRepo() {
    var repo = System.getenv(MAVEN_PROP);
    if (repo == null) {
            return DEFAULT_MAVEN_REPO;
     } else {
            return repo;
     }
}

What should I do to resolve "java.net.UnknownHostException".

[timfel]

As you saw you can just set the environment variable org.graalvm.maven.downloader.repository if you want to point to a maven mirror.

env 'org.graalvm.maven.downloader.repository=http://my.maven.internal.repo/' graalpy -m standalone --verbose native --module test.py --output test --venv venv

Make sure your mirror is reachable though, otherwise it'll look like this:

using GRAALVM: /home/tim/.sdkman/candidates/java/23-graal
  native_image: /home/tim/.sdkman/candidates/java/23-graal/bin/native-image
  javac: /home/tim/.sdkman/candidates/java/23-graal/bin/javac
downloading graalpython maven artifacts: /home/tim/.pyenv/versions/graalpy-24.2.1/libexec/graalpy-polyglot-get -a python-embedding -g org.graalvm.python -v 24.2.1 -o /home/tim/.pyenv/versions/graalpy-24.2.1/downloaded_standalone_resources
Jun 04, 2025 7:49:50 PM org.graalvm.maven.downloader.Main main
INFO: downloading org.graalvm.python:python-embedding:24.2.1 from http://my.maven.internal.repo/ to /home/tim/.pyenv/versions/graalpy-24.2.1/downloaded_standalone_resources
Jun 04, 2025 7:49:50 PM org.graalvm.maven.downloader.MVNDownloader getProxy
INFO: using proxy 'https://my.corporations.proxy:8080'
Jun 04, 2025 7:49:50 PM org.graalvm.maven.downloader.MVNDownloader downloadMavenFile
WARNING: could not download maven file from http://my.maven.internal.repo/org/graalvm/python/python-embedding/24.2.1/python-embedding-24.2.1.pom, because of: java.io.IOException: Skipping download from http://my.maven.internal.repo/org/graalvm/python/python-embedding/24.2.1/python-embedding-24.2.1.pom due to response code 502. Falling back on https://repo1.maven.org/maven2

[kuanyan9527]

Thanks @timfel your method works, but a new error occurred:
WARNING: could not download maven file from http://my.maven.internal.repo/org/graalvm/python/python-embedding/24.2.1/python-embedding-24.2.1.pom, because of: javax.net.ssl.SSLHandshakeException: (certificate_unknown) PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target. Falling back on https://repo1.maven.org/maven2/
I googled and found a solution

keytool -import -noprompt -trustcacerts -alias mymavenrepo.crt -file $JAVA_HOME/lib/security/mymavenrepo.crt -keystore $JAVA_HOME/lib/security/cacerts -storepass changeit

Unfortunately, it doesn't seem to work.

[timfel]

@kuanyan9527 if your custom repository is inside your org, you don't need the proxy. try unsetting the proxy environment variables to access it without a proxy

[kuanyan9527]

Yes, it is the internal Maven repository. I have unset the proxy, but an SSLHandshakeException error occurred.

[timfel]

Hm, then I don't know, sorry, We just use URLConnection conn = url.openConnection(getProxy());, but this is running AOT compiled, so nothing you do to your JAVA_HOME will affect this.