could'nt run wallettemplate project in bitcoinJ
Bytecode version 55 is Java 11. The JavaFX from openjfx that you are using was compiled with Java 11, but you are compiling with Java 8. Java 8 already includes JavaFX, so you don't have to add it via maven from openjfx. So you can either upgrade to OpenJDK Java 11, or remove the openjfx dependency from your project.