with a single click because they are written in different programming languages: Java uses Java code, while Bedrock uses C++ and JSON-based scripts.
Example skeleton for behavior_pack/entities/my_dragon.json : how to convert jar to mcaddon
There is no automated tool to convert complex gameplay code (like new machines or dimensions) from Java to Bedrock. You must manually "port" the content: Convert JAR to ZIP Online | No Software Needed with a single click because they are written