Added the j2re for Linux. My installation of Eclipse runs on an j2re installed in Nix, so I guess it works pretty well. Of course other platforms should be added. This version will not be installed if the platform is not i686-linux.

svn path=/nixpkgs/trunk/; revision=714

pkgs/development/interpreters/j2re/builder.sh

@@ -0,0 +1,14 @@
+#!/bin/sh
+
+. $stdenv/setup || exit 1
+version=j2re1.4.2_03
+
+cp $src $version.bin || exit 1
+chmod u+x $version.bin || exit 1
+
+alias more=cat
+
+yes yes | ./$version.bin || exit 1
+
+mkdir $out || exit 1
+mv $version/* $out/ || exit 1

pkgs/development/interpreters/j2re/default.nix

@@ -0,0 +1,10 @@
+{stdenv, fetchurl}: 
+
+if stdenv.system == "i686-linux"
+  then
+    (import ./j2re-sun-linux.nix) {
+      stdenv   = stdenv;
+      fetchurl = fetchurl;
+    }
+  else
+    false

pkgs/development/interpreters/j2re/j2re-sun-linux.nix

@@ -0,0 +1,15 @@
+{stdenv, fetchurl}: 
+
+assert stdenv.system == "i686-linux";
+
+
+derivation {
+  name = "j2re-1.4.2";
+  system = stdenv.system;
+  builder = ./builder.sh;
+  src = fetchurl {
+      url = http://www.java.sun.com/webapps/download/AutoDL?BundleId=9500;
+      md5 = "b4aae3fcda73d976bd6ae6349b36a90c";
+    };
+  stdenv = stdenv;
+}

pkgs/system/all-packages-generic.nix

@@ -220,6 +220,16 @@
     stdenv = stdenv;
   };
 
+  python = (import ../development/interpreters/python) {
+    fetchurl = fetchurl;
+    stdenv = stdenv;
+  };
+
+  j2re = (import ../development/interpreters/j2re) {
+    fetchurl = fetchurl;
+    stdenv = stdenv;
+  };
+
   pcre = (import ../development/libraries/pcre) {
     fetchurl = fetchurl;
     stdenv = stdenv;