I tracked down the java application start delay. It was IPv6 related problem. My firewall (shorewall) configuration was to disable all IPv6 outgoing traffic, also to loopback address. For some reason, any java application that wanted to do any network connection, also tried to establish an IPv6 connection.
tcp 0 1 ::1:44406 ::1:32776 SYN_SENT 15241/java
There is "DISABLE_IPV6" option in shorewall.conf, but it setting it to "No" and restarting Shorewall didn't help, so I removed IPv6 support from the kernel, and now all java applications start immediately.