diff --git a/java/gen.go b/java/gen.go
new file mode 100644
index 0000000..0b84d44
--- /dev/null
+++ b/java/gen.go
@@ -0,0 +1,79 @@
+// Copyright 2015 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package java
+
+// This file generates the final rules for compiling all C/C++.  All properties related to
+// compiling should have been translated into builderFlags or another argument to the Transform*
+// functions.
+
+import (
+	"path/filepath"
+	"strings"
+
+	"github.com/google/blueprint"
+	"github.com/google/blueprint/pathtools"
+
+	"android/soong/common"
+)
+
+func init() {
+	pctx.VariableFunc("aidlCmd", func(c interface{}) (string, error) {
+		return c.(common.Config).HostBinTool("aidl")
+	})
+	pctx.VariableConfigMethod("srcDir", common.Config.SrcDir)
+}
+
+var (
+	aidl = pctx.StaticRule("aidl",
+		blueprint.RuleParams{
+			Command:     "$aidlCmd -d$depFile $aidlFlags $in $out",
+			Description: "aidl $out",
+		},
+		"depFile", "aidlFlags")
+)
+
+func genAidl(ctx common.AndroidModuleContext, aidlFile, aidlFlags string) string {
+	javaFile := strings.TrimPrefix(aidlFile, common.ModuleSrcDir(ctx))
+	javaFile = filepath.Join(common.ModuleGenDir(ctx), javaFile)
+	javaFile = pathtools.ReplaceExtension(javaFile, "java")
+	depFile := javaFile + ".d"
+
+	ctx.Build(pctx, blueprint.BuildParams{
+		Rule:      aidl,
+		Outputs:   []string{javaFile},
+		Inputs:    []string{aidlFile},
+		Implicits: []string{"$aidlCmd"},
+		Args: map[string]string{
+			"depFile":   depFile,
+			"aidlFlags": aidlFlags,
+		},
+	})
+
+	return javaFile
+}
+
+func genSources(ctx common.AndroidModuleContext, srcFiles []string,
+	flags javaBuilderFlags) []string {
+
+	for i, srcFile := range srcFiles {
+		switch filepath.Ext(srcFile) {
+		case ".aidl":
+			javaFile := genAidl(ctx, srcFile, flags.aidlFlags)
+			srcFiles[i] = javaFile
+		}
+	}
+
+	return srcFiles
+}