java - can't install STS 3.8.4 on Ubuntu 12.04 -

i run interesting problem. have machine ubuntu 12.04 sts , wanted install sts 3.8.4. have jdk 8 installed when try run sts message "version 1.6.0_41 of jvm not suitable product. version: 1.8 or greater required." so, i've had on , few forum, discovered command sudo update-alternatives --config java these results:

linux-dell-system-xps-l702x:~/opt$ sudo update-alternatives --config java there 2 choices alternative java (providing /usr/bin/java).    selection    path                                            priority   status ------------------------------------------------------------   0            /usr/lib/jvm/java-6-openjdk-amd64/jre/bin/java   1061      auto mode * 1            /usr/lib/jvm/java-6-openjdk-amd64/jre/bin/java   1061      manual mode   2            /usr/lib/jvm/java-7-openjdk-amd64/jre/bin/java   1051      manual mode  press enter keep current choice[*], or type selection number: 2 

still no jdk 8, which, said, installed on machine because use eclipse. now, there way manually set in kind of sts configuration file far know or other way seem fail identify?