How to decompile java jar

$ git clone https://github.com/fesh0r/fernflower

$ cd fernflower

# build the source code using Gradle build tool
$ gradle build

# the fernflower.jar at build/lib/

 

# decompile JAR or Class files
# java -jar fernflower.jar /path/asm-analysis-3.2.jar /path/unknown.class /path/decompile/

$ java -jar fernflower.jar /path/asm-analysis-3.2.jar /path/decompile/

INFO:  Decompiling class org/objectweb/asm/tree/analysis/Analyzer
INFO:  ... done
INFO:  Decompiling class org/objectweb/asm/tree/analysis/AnalyzerException
INFO:  ... done
INFO:  Decompiling class org/objectweb/asm/tree/analysis/BasicInterpreter
INFO:  ... done

https://mkyong.com/java/how-to-decompile-class-in-java/