diff --git a/java/dexpreopt_config.go b/java/dexpreopt_config.go
new file mode 100644
index 0000000..6af839b
--- /dev/null
+++ b/java/dexpreopt_config.go
@@ -0,0 +1,154 @@
+// Copyright 2019 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
+
+import (
+	"android/soong/android"
+	"android/soong/dexpreopt"
+	"path/filepath"
+	"strings"
+)
+
+// dexpreoptGlobalConfig returns the global dexpreopt.config.  It is loaded once the first time it is called for any
+// ctx.Config(), and returns the same data for all future calls with the same ctx.Config().  A value can be inserted
+// for tests using setDexpreoptTestGlobalConfig.
+func dexpreoptGlobalConfig(ctx android.PathContext) dexpreopt.GlobalConfig {
+	return ctx.Config().Once(dexpreoptGlobalConfigKey, func() interface{} {
+		if f := ctx.Config().DexpreoptGlobalConfig(); f != "" {
+			ctx.AddNinjaFileDeps(f)
+			globalConfig, err := dexpreopt.LoadGlobalConfig(ctx, f)
+			if err != nil {
+				panic(err)
+			}
+			return globalConfig
+		}
+
+		// No global config filename set, see if there is a test config set
+		return ctx.Config().Once(dexpreoptTestGlobalConfigKey, func() interface{} {
+			// Nope, return a config with preopting disabled
+			return dexpreopt.GlobalConfig{
+				DisablePreopt: true,
+			}
+		})
+	}).(dexpreopt.GlobalConfig)
+}
+
+// setDexpreoptTestGlobalConfig sets a GlobalConfig that future calls to dexpreoptGlobalConfig will return.  It must
+// be called before the first call to dexpreoptGlobalConfig for the config.
+func setDexpreoptTestGlobalConfig(config android.Config, globalConfig dexpreopt.GlobalConfig) {
+	config.Once(dexpreoptTestGlobalConfigKey, func() interface{} { return globalConfig })
+}
+
+var dexpreoptGlobalConfigKey = android.NewOnceKey("DexpreoptGlobalConfig")
+var dexpreoptTestGlobalConfigKey = android.NewOnceKey("TestDexpreoptGlobalConfig")
+
+// systemServerClasspath returns the on-device locations of the modules in the system server classpath.  It is computed
+// once the first time it is called for any ctx.Config(), and returns the same slice for all future calls with the same
+// ctx.Config().
+func systemServerClasspath(ctx android.PathContext) []string {
+	return ctx.Config().OnceStringSlice(systemServerClasspathKey, func() []string {
+		global := dexpreoptGlobalConfig(ctx)
+
+		var systemServerClasspathLocations []string
+		for _, m := range global.SystemServerJars {
+			systemServerClasspathLocations = append(systemServerClasspathLocations,
+				filepath.Join("/system/framework", m+".jar"))
+		}
+		return systemServerClasspathLocations
+	})
+}
+
+var systemServerClasspathKey = android.NewOnceKey("systemServerClasspath")
+
+// defaultBootImageConfig returns the bootImageConfig that will be used to dexpreopt modules.  It is computed once the
+// first time it is called for any ctx.Config(), and returns the same slice for all future calls with the same
+// ctx.Config().
+func defaultBootImageConfig(ctx android.PathContext) bootImageConfig {
+	return ctx.Config().Once(defaultBootImageConfigKey, func() interface{} {
+		global := dexpreoptGlobalConfig(ctx)
+
+		runtimeModules := global.RuntimeApexJars
+		nonFrameworkModules := concat(runtimeModules, global.ProductUpdatableBootModules)
+		frameworkModules := android.RemoveListFromList(global.BootJars, nonFrameworkModules)
+
+		var nonUpdatableBootModules []string
+		var nonUpdatableBootLocations []string
+
+		for _, m := range runtimeModules {
+			nonUpdatableBootModules = append(nonUpdatableBootModules, m)
+			nonUpdatableBootLocations = append(nonUpdatableBootLocations,
+				filepath.Join("/apex/com.android.runtime/javalib", m+".jar"))
+		}
+
+		for _, m := range frameworkModules {
+			nonUpdatableBootModules = append(nonUpdatableBootModules, m)
+			nonUpdatableBootLocations = append(nonUpdatableBootLocations,
+				filepath.Join("/system/framework", m+".jar"))
+		}
+
+		// The path to bootclasspath dex files needs to be known at module GenerateAndroidBuildAction time, before
+		// the bootclasspath modules have been compiled.  Set up known paths for them, the singleton rules will copy
+		// them there.
+		// TODO: use module dependencies instead
+		var nonUpdatableBootDexPaths android.WritablePaths
+		for _, m := range nonUpdatableBootModules {
+			nonUpdatableBootDexPaths = append(nonUpdatableBootDexPaths,
+				android.PathForOutput(ctx, ctx.Config().DeviceName(), "dex_bootjars_input", m+".jar"))
+		}
+
+		dir := android.PathForOutput(ctx, ctx.Config().DeviceName(), "dex_bootjars")
+		symbolsDir := android.PathForOutput(ctx, ctx.Config().DeviceName(), "dex_bootjars_unstripped")
+		images := make(map[android.ArchType]android.OutputPath)
+
+		for _, target := range ctx.Config().Targets[android.Android] {
+			images[target.Arch.ArchType] = dir.Join(ctx,
+				"system/framework", target.Arch.ArchType.String(), "boot.art")
+		}
+
+		return bootImageConfig{
+			name:         "boot",
+			modules:      nonUpdatableBootModules,
+			dexLocations: nonUpdatableBootLocations,
+			dexPaths:     nonUpdatableBootDexPaths,
+			dir:          dir,
+			symbolsDir:   symbolsDir,
+			images:       images,
+		}
+	}).(bootImageConfig)
+}
+
+var defaultBootImageConfigKey = android.NewOnceKey("defaultBootImageConfig")
+
+func defaultBootclasspath(ctx android.PathContext) []string {
+	return ctx.Config().OnceStringSlice(defaultBootclasspathKey, func() []string {
+		global := dexpreoptGlobalConfig(ctx)
+		image := defaultBootImageConfig(ctx)
+		bootclasspath := append(copyOf(image.dexLocations), global.ProductUpdatableBootLocations...)
+		return bootclasspath
+	})
+}
+
+var defaultBootclasspathKey = android.NewOnceKey("defaultBootclasspath")
+
+var copyOf = android.CopyOf
+
+func init() {
+	android.RegisterMakeVarsProvider(pctx, dexpreoptConfigMakevars)
+}
+
+func dexpreoptConfigMakevars(ctx android.MakeVarsContext) {
+	ctx.Strict("PRODUCT_BOOTCLASSPATH", strings.Join(defaultBootclasspath(ctx), ":"))
+	ctx.Strict("PRODUCT_SYSTEM_SERVER_CLASSPATH", strings.Join(systemServerClasspath(ctx), ":"))
+}