Compile any class e.g.

class A {
}

and get the javap's output with "-c" or "-v" option.

The instruction mnemonics "aload_0" and "return" is followed by unnecessary spaces:
....
       0: aload_0
       1: invokespecial #1 // Method java/lang/Object."<init>":()V
       4: return
.....

Hex dump for aload_0 string:
20 20 20 20 20 20 20 30 3A 20 61 6C 6F 61 64 5F 30 20 20 20 20 20 20 20 0D 0A