Add prerequisites section to README for building the extension

Author: jakbin

README.md

@@ -21,6 +21,13 @@ For more information about the protocol visit: [modelcontextprotocol.io](https:/
 
 ## Installation
 
+### Prerequisites
+
+Ensure that the following prerequisites are met before building and installing the extension:
+
+1. **Java**: Java must be installed and available in your system's PATH. You can verify this by running `java --version` in your terminal.
+2. **jar Command**: The `jar` command must be executable and available in your system's PATH. You can verify this by running `jar --version` in your terminal. This is required for building and installing the extension.
+
 ### Building the Extension
 
 1. **Clone the Repository**: Obtain the source code for the MCP Server Extension.