diff --git a/pkgs/development/compilers/openjdk/default.nix b/pkgs/development/compilers/openjdk/default.nix
index 5f5148911ec2..f243baab5919 100644
--- a/pkgs/development/compilers/openjdk/default.nix
+++ b/pkgs/development/compilers/openjdk/default.nix
@@ -21,6 +21,21 @@
 , jreOnly ? false
 }:
 
+let
+
+  /**
+   * The JRE libraries are in directories that depend on the CPU.
+   */
+  architecture =
+    if stdenv.system == "i686-linux" then
+      "i386"
+    else if stdenv.system == "x86_64-linux" then
+      "amd64"
+    else
+      throw "openjdk requires i686-linux or x86_64 linux";
+
+in
+
 stdenv.mkDerivation rec {
   name = "openj${if jreOnly then "re" else "dk"}-7b127";
 
@@ -137,5 +152,7 @@ stdenv.mkDerivation rec {
 
     platforms = stdenv.lib.platforms.linux;
   };
+
+  passthru = { inherit architecture; };
 }
 
diff --git a/pkgs/development/compilers/openjdk/make-bootstrap.nix b/pkgs/development/compilers/openjdk/make-bootstrap.nix
index aa5b8ad39f56..090a1479741a 100644
--- a/pkgs/development/compilers/openjdk/make-bootstrap.nix
+++ b/pkgs/development/compilers/openjdk/make-bootstrap.nix
@@ -1,6 +1,6 @@
 { runCommand, openjdk, nukeReferences }:
 
-let arch = if openjdk.system == "x86_64-linux" then "amd64" else "i386"; in
+let arch = openjdk.architecture; in
 
 runCommand "${openjdk.name}-bootstrap.tar.xz" {} ''
   mkdir -p openjdk-bootstrap/bin