Decompilers do have some uses. They should not , however , be used to analyse malware (Those are all separate links, and all seem to endorse JD-GUI. One even claims it's the "best")

For what it's worth, if you do find yourself with legitimate cause to use a decompiler, I'd recommend CFR or Procyon. If you intend to analyse malware, my recommendation would be that you use a disassembler, such as Krakatau

(Adding to) The decompiler's output

JD-web isn't a thing any more, so I can't lead with rickroll via decompiler

Escape sequences JavaP*
Playing with names
* JavaP is a disassembler, not a decompiler

The decompiler itself

Inner classes Fernflower, CFR, JD-GUI, Procyon
goto_w JD-GUI, Procyon
jsr_w JD-GUI, Procyon, CFR
Synthetic members JD-GUI, Procyon
Going backwards! JD-GUI

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