Is it possible to Install Eclipse 4 and get it to work with Oracle JDK7 on Ubuntu 12.04 x64? The best way would be a PPA to apt-get upgrade newer versions. A "portable" istall would be okay, too.
What you can do is downloading the Eclipse software on the Eclipse website (eclipse.org). The whole program is contained in the archive you download. After downloading this, you can unpack it and put the folder you get on a portable device.
For Java 7, you can do the same thing. Downloading the JDK7 from the Oracle website and install it on the same portable device as Eclipse. Once you do that, you should tell Eclipse that you want to use this JDK for your coding activities.
But I recognize that you will have to update it manually.