- the byte code was compiled from a different language than Java, or
- an obfuscator was used to change the byte code after it was compiled.
The soul is dyed the color of its thoughts. Think only on those things that are in line with your principles and can bear the light of day. The content of your character is your choice. Day by day, what you do is who you become. Your integrity is your destiny - it is the light that guides your way. - Heraclitus
Decompiled code can contain goto statements because the JVM bytecode has them. If the decompiler can't re-construct Java code for some section of bytecode, it attempts a pseudo-code translation where the gotos are preserved. To get that to compile with a Java compiler, someone would need to translate those into equivalent Java constructs. "Jad" is one of the better-known decompilers that does this.