$ diff <(javap -c -p OldWay) <(javap -c -p NewWay)     (25.0.4.1+1-LTS, class name normalised to X)
no differences (57 lines of javap output each)

$ cmp OldWay.class NewWay.class     (javac -g:none; NewWay renamed to OldWay inside the class file)
identical, byte for byte (2249 bytes)

$ diff <(javap -c -p -l OldWay) <(javap -c -p -l NewWay)     (default javac -g keeps line numbers)
8c8
<         line 9: 0
---
>         line 3: 0
52,57c52,57
<         line 11: 0
<         line 12: 14
<         line 13: 25
<         line 14: 37
<         line 15: 44
<         line 16: 90
---
>         line 5: 0
>         line 6: 14
>         line 7: 25
>         line 8: 37
>         line 9: 44
>         line 10: 90
67c67
<         line 13: 0
---
>         line 7: 0