diff --git a/pkgs/development/interpreters/jre/builder.sh b/pkgs/development/interpreters/jre/builder.sh
index 8ddd87622653..91ef8ca2fc1f 100644
--- a/pkgs/development/interpreters/jre/builder.sh
+++ b/pkgs/development/interpreters/jre/builder.sh
@@ -1,19 +1,11 @@
-#! /bin/sh
+source $stdenv/setup
 
-source $stdenv/setup || exit 1
+unzip $src || true
 
-cp $src $version.bin || exit 1
-chmod u+x $version.bin || exit 1
-
-alias more=cat
-
-echo "Unpacking J2RE"
-yes yes | ./$version.bin || exit 1
-
-mkdir $out || exit 1
+ensureDir $out
 
 echo "Moving sources to the right location"
-mv $version/* $out/ || exit 1
+mv $version/* $out/
 
 echo "Removing files at top level"
 for file in $out/*
@@ -23,3 +15,19 @@ do
   fi
 done
 rm -rf $out/docs
+
+# Set the dynamic linker.
+rpath=
+for i in $libraries; do
+    rpath=$rpath${rpath:+:}$i/lib
+done
+find $out -type f -perm +100 \
+    -exec patchelf --interpreter "$(cat $NIX_GCC/nix-support/dynamic-linker)" \
+    --set-rpath "$rpath" {} \;
+
+# Unpack .pack files.
+for i in $(find $out -name "*.pack"); do
+    echo "unpacking $i..."
+    $out/bin/unpack200 "$i" "$(dirname $i)/$(basename $i .pack).jar"
+    rm "$i"
+done
diff --git a/pkgs/development/interpreters/jre/default.nix b/pkgs/development/interpreters/jre/default.nix
index fd81dd18ceea..6e694202fd70 100644
--- a/pkgs/development/interpreters/jre/default.nix
+++ b/pkgs/development/interpreters/jre/default.nix
@@ -1,9 +1,9 @@
-{stdenv, fetchurl}: 
+{stdenv, fetchurl, unzip}: 
 
 if stdenv.system == "i686-linux"
   then
     (import ./jre-sun-linux.nix) {
-      inherit stdenv fetchurl;
+      inherit stdenv fetchurl unzip;
     }
   else
     false
diff --git a/pkgs/development/interpreters/jre/jre-sun-linux.nix b/pkgs/development/interpreters/jre/jre-sun-linux.nix
index 833d30cde6c2..274d737e2e2e 100644
--- a/pkgs/development/interpreters/jre/jre-sun-linux.nix
+++ b/pkgs/development/interpreters/jre/jre-sun-linux.nix
@@ -1,4 +1,4 @@
-{stdenv, fetchurl}: 
+{stdenv, fetchurl, unzip}: 
 
 assert stdenv.system == "i686-linux";
 
@@ -10,6 +10,7 @@ assert stdenv.system == "i686-linux";
     url = http://jdl.sun.com/webapps/download/AutoDL?BundleId=10542;
     md5 = "e2ad1c9e47f3e34d1efae059b9e2a2d9";
   };
+  buildInputs = [unzip];
 })
 
 // {mozillaPlugin = "/plugin/i386/ns7";}
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index 851875f407a9..d3b13ef9ad3c 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -865,7 +865,7 @@ rec {
   };
 
   jre = import ../development/interpreters/jre {
-    inherit fetchurl stdenv;
+    inherit fetchurl stdenv unzip;
   };
 
   kaffe =  import ../development/interpreters/kaffe {