JVM: Inspect class files with `javap`

javap can be used to inspect the generated bytecode in a java .class file.

For example, given a kotlin file, foo.kt:

// foo.kt
fun main() {
    println("Hello, world!")
}

Compile it to a class file:

kotlinc -d out foo.kt
tree out
# out
# ├── FooKt.class
# └── META-INF
#     └── main.kotlin_module

Then inspect the generated bytecode:

javap -c out/FooKt.class
# Compiled from "foo.kt"
# public final class FooKt {
#   public static final void main();
#     Code:
#        0: ldc           #8                  // String Hello, world!
#        2: getstatic     #14                 // Field java/lang/System.out:Ljava/io/PrintStream;
#        5: swap
#        6: invokevirtual #20                 // Method java/io/PrintStream.println:(Ljava/lang/Object;)V
#        9: return
# 
#   public static void main(java.lang.String[]);
#     Code:
#        0: invokestatic  #23                 // Method main:()V
#        3: return
# }