For example, as a post-compilation step you could massage the .class data to make the byte code either harder to read when decompiled or harder to decompile into valid Java code (or both).

Java famously runs on billions of devices, including workstations, desktops, tablets, supercomputers, and jewelry. Yes, jewelry. Look it up. [Michael] realized Java doesn’t run on Commodore 6… ...

The most copied StackOverflow Java code snippet of all time contains a bug. ... The code snippet printed byte counts (123,456,789 bytes) in a human-readable format, like 123.5 MB.