Java got its slow reputation mainly because any early encounter with a Java applet would proudly display the Java logo and then cause your computer and disk to thrash for 30 seconds.

Then Java developers heard this, confused it for "Java executes slowly" and so they never fixed it, until Java applets just became obsolete.

Eclipse didn't help Java's reputation any.

"Amazing new IDE has just come out! Good luck running it!"

Also local Swing apps were memory hogs compared for the time. 20MB was a lot on a machine that had 256 or 512MB in total.