The jad official website does not provide support for jad after eclipse 3.3
Later, I found a simple installation method on the foreign website
Original post address: https://marketplace.eclipse.org/content/eclipse-class-decompiler
This method can support eclipse version:
Neon (4.6), Mars (4.5), Luna (4.4), Kepler (4.3), Juno (4.2, 3.8), Previous to Juno (<=4.1), Oxygen (4.7)
Drag the eclipse icon below to your open eclipse workspace. Then select all, next, OK,. . .
over！