grpc/grpc-java · error · UnsupportedOperationException

Unsupported operation getLocalAddress()

Error message

Unsupported operation getLocalAddress()

What it means

UdsSocket emulates java.net.Socket over an Android LocalSocket. A Unix Domain Socket has no IP local address, so getLocalAddress() intentionally throws UnsupportedOperationException. UdsSocket instead exposes getLocalSocketAddress() returning an opaque, typeless SocketAddress placeholder.

Source

Thrown at android/src/main/java/io/grpc/android/UdsSocket.java:118

  @Override
  public InputStream getInputStream() throws IOException {
    return new FilterInputStream(localSocket.getInputStream()) {
      @Override
      public void close() throws IOException {
        UdsSocket.this.close();
      }
    };
  }

  @Override
  public boolean getKeepAlive() {
    throw new UnsupportedOperationException("Unsupported operation getKeepAlive()");
  }

  @Override
  public InetAddress getLocalAddress() {
    throw new UnsupportedOperationException("Unsupported operation getLocalAddress()");
  }

  @Override
  public int getLocalPort() {
    throw new UnsupportedOperationException("Unsupported operation getLocalPort()");
  }

  @Override
  public SocketAddress getLocalSocketAddress() {
    return new SocketAddress() {};
  }

  @Override
  public boolean getOOBInline() {
    throw new UnsupportedOperationException("Unsupported operation getOOBInline()");
  }

  @Override

View on GitHub (pinned to 64daddc1f3)

Solutions

1. Skip IP-local-address capture for UDS sockets; identify the endpoint by the UDS path instead.
2. Guard with a UdsSocket check or catch UnsupportedOperationException in shared socket-inspection code.
3. Use getLocalSocketAddress()'s placeholder only for existence checks, never for address data.

Example fix

// before
InetAddress local = socket.getLocalAddress();
// after
InetAddress local = socket.getClass().getSimpleName().equals("UdsSocket")
    ? null
    : socket.getLocalAddress();

static boolean isUdsSocket(Socket s) {
  return s.getClass().getName().equals("io.grpc.android.UdsSocket");
}

try {
  InetAddress local = socket.getLocalAddress();
} catch (UnsupportedOperationException e) {
  // UDS: no IP local address; use the configured UDS path
}

When it happens

Trigger: Calling getLocalAddress() on the UdsSocket created by UdsSocketFactory — e.g. bind/audit logging, connection-tracking code, or libraries that record both local and remote InetAddress for every socket.

Common situations: Network telemetry frameworks assuming IP sockets; security/audit code capturing local bind addresses; tests verifying socket state.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

• getChannel() not supported
• getInetAddress() not supported
• Unsupported operation getLocalPort()
• Unsupported operation getKeepAlive()
• Unsupported operation getOOBInline()

AI-assisted analysis of grpc/grpc-java@64daddc1f3 (2026-09-08). Data as JSON: /api/errors/5d06710171f0333a. Report an issue: GitHub.