How to Resolve InvocationTargetException in Java Web Start with Java 9 EA?

What are the steps to resolve InvocationTargetException when using Java Web Start with Java 9 early access?

// Sample code snippet to simulate InvocationTargetException

public class ExampleApp {
    public static void main(String[] args) {
        try {
            // Simulating the invocation that may throw an exception
            runMainProcess();
        } catch (Exception e) {
            e.printStackTrace(); // Log the exception for debugging
        }
    }

    private static void runMainProcess() throws Exception {
        // Simulate an error
        throw new Exception("Simulated error");
    }
}

InvocationTargetException occurs when an exception is thrown by an invoked method or constructor through reflection. This can be particularly troublesome in Java Web Start applications using Java 9 EA due to various compatibility and configuration issues.

// Example JNLP configuration
<application-desc main-class="com.example.MainClass">
    <j2se version="1.9+" />
    <resources>
        <jardir href="resources/" />
        <jar href="app.jar" main="true" />
    </resources>
    <security>
        <all-permissions />
    </security>
</application-desc>

Causes

• Incompatible Java version or early access build issues.
• Issues with classpath not set correctly for the Java Web Start application.
• Faulty JNLP (Java Network Launch Protocol) file configurations.

Solutions

• Ensure you are using a stable version of Java, as early access builds can have bugs.
• Verify that your JNLP file is correctly configured with the right references and permissions.
• Check the console logs to identify the root cause of the exception and fix it accordingly.

Mistake: Using an unsupported Java version with Web Start.

Solution: Switch to a stable Java version compatible with your application.

Mistake: Not including all necessary resources in the JNLP.

Solution: Check and update the JNLP to include all required jar files and resources.

Mistake: Ignoring console error logs after execution.

Solution: Always review the Java console output for detailed error messages related to InvocationTargetException.