How to Resolve the Eclipse Error: "Failed to Connect to Remote VM"

What causes Eclipse to show the error "Failed to connect to remote VM" during debugging?

The error message 'Failed to connect to remote VM. Connection Refused' indicates that Eclipse is unable to establish a connection to the Java Virtual Machine (JVM) that you are trying to debug. This can stem from various reasons, including incorrect configuration settings, a non-responsive target application, or network issues.

// Example of VM arguments for Remote Debugging:
-javaagent:jdwp=transport=dt_socket,server=y,suspend=n,address=*:5005

// This should be added to the JVM args of the application you wish to debug.

Causes

• The target JVM is not running or has not been started in debug mode.
• The port specified in Eclipse does not match the port on which the JVM is listening.
• Firewall or security settings are blocking the connection.
• Incorrect configuration of JVM parameters in Eclipse.

Solutions

• Ensure that the target application is started with the correct parameters for remote debugging. For example, use the following JVM arguments: ```bash -agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=*:5005 ``` This command line tells the JVM to listen for a debugger on port 5005.
• Check that the port number in your Eclipse Debug Configuration matches the port number used in the target JVM settings.
• Make sure that any firewalls or antivirus programs are configured to allow connections on the specified port.
• Restart Eclipse and the target application to rule out transient issues.

Mistake: Forgetting to start the target application in debug mode.

Solution: Ensure that the application is launched with debug parameters.

Mistake: Using an incorrect port number in Eclipse settings.

Solution: Verify that the ports match between your Eclipse configuration and the application.

Mistake: Not checking for firewall or security software that might block the connection.

Solution: Review and adjust firewall settings to allow connections on the chosen port.