You can install all plugins into firefox or mozilla, then configure konqueror to use the plugins, by pointing it to the firefox or mozilla plugin directory. Do as follows,
1) start konqueror
2) go to settings
3) go to plugins
4) set the plugin directory for your mozilla or firefox installation
5) click search for new plugins
Konqueror should then work ok with your plugins. To use java, there is a seperate configuration option for this in konqueror settings.