Learn the essentials of error handling in C# with try-catch blocks, optimize application performance using .NET performance monitoring, and troubleshoot Java’s "illegal start of expression" error in this comprehensive guide. Discover best practices for managing exceptions, enhancing application responsiveness, and fixing common Java syntax issues. This blog covers critical insights for developers, including tools like Stackify Retrace for .NET monitoring, proper use of catch blocks in C#, and debugging tips for Java. Whether you're a beginner or experienced developer, these strategies will help you build robust, high-performing applications with efficient error management and performance optimization techniques.