diff --git a/java/boot_jars.go b/java/boot_jars.go
new file mode 100644
index 0000000..900eb7a
--- /dev/null
+++ b/java/boot_jars.go
@@ -0,0 +1,123 @@
+// Copyright 2020 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"
+)
+
+func init() {
+	android.RegisterSingletonType("boot_jars", bootJarsSingletonFactory)
+}
+
+func bootJarsSingletonFactory() android.Singleton {
+	return &bootJarsSingleton{}
+}
+
+type bootJarsSingleton struct{}
+
+func populateMapFromConfiguredJarList(ctx android.SingletonContext, moduleToApex map[string]string, list android.ConfiguredJarList, name string) bool {
+	for i := 0; i < list.Len(); i++ {
+		module := list.Jar(i)
+		// Ignore jacocoagent it is only added when instrumenting and so has no impact on
+		// app compatibility.
+		if module == "jacocoagent" {
+			continue
+		}
+		apex := list.Apex(i)
+		if existing, ok := moduleToApex[module]; ok {
+			ctx.Errorf("Configuration property %q is invalid as it contains multiple references to module (%s) in APEXes (%s and %s)",
+				module, existing, apex)
+			return false
+		}
+
+		moduleToApex[module] = apex
+	}
+
+	return true
+}
+
+func (b *bootJarsSingleton) GenerateBuildActions(ctx android.SingletonContext) {
+	config := ctx.Config()
+	if config.SkipBootJarsCheck() {
+		return
+	}
+
+	// Populate a map from module name to APEX from the boot jars. If there is a problem
+	// such as duplicate modules then fail and return immediately.
+	moduleToApex := make(map[string]string)
+	if !populateMapFromConfiguredJarList(ctx, moduleToApex, config.NonUpdatableBootJars(), "BootJars") ||
+		!populateMapFromConfiguredJarList(ctx, moduleToApex, config.UpdatableBootJars(), "UpdatableBootJars") {
+		return
+	}
+
+	// Map from module name to the correct apex variant.
+	nameToApexVariant := make(map[string]android.Module)
+
+	// Scan all the modules looking for the module/apex variants corresponding to the
+	// boot jars.
+	ctx.VisitAllModules(func(module android.Module) {
+		name := ctx.ModuleName(module)
+		if apex, ok := moduleToApex[name]; ok {
+			apexInfo := ctx.ModuleProvider(module, android.ApexInfoProvider).(android.ApexInfo)
+			if (apex == "platform" && apexInfo.IsForPlatform()) || apexInfo.InApex(apex) {
+				// The module name/apex variant should be unique in the system but double check
+				// just in case something has gone wrong.
+				if existing, ok := nameToApexVariant[name]; ok {
+					ctx.Errorf("found multiple variants matching %s:%s: %q and %q", apex, name, existing, module)
+				}
+				nameToApexVariant[name] = module
+			}
+		}
+	})
+
+	timestamp := android.PathForOutput(ctx, "boot-jars-package-check/stamp")
+
+	rule := android.NewRuleBuilder()
+	checkBootJars := rule.Command().BuiltTool(ctx, "check_boot_jars").
+		Input(android.PathForSource(ctx, "build/soong/scripts/check_boot_jars/package_allowed_list.txt"))
+
+	// If this is not an unbundled build and missing dependencies are not allowed
+	// then all the boot jars listed must have been found.
+	strict := !config.UnbundledBuild() && !config.AllowMissingDependencies()
+
+	// Iterate over the module names on the boot classpath in order
+	for _, name := range android.SortedStringKeys(moduleToApex) {
+		if apexVariant, ok := nameToApexVariant[name]; ok {
+			if dep, ok := apexVariant.(Dependency); ok {
+				// Add the implementation jars for the module to be checked. This uses implementation
+				// and resources jar as that is what the previous make based check uses.
+				for _, jar := range dep.ImplementationAndResourcesJars() {
+					checkBootJars.Input(jar)
+				}
+			} else if _, ok := apexVariant.(*DexImport); ok {
+				// TODO(b/171479578): ignore deximport when doing package check until boot_jars.go can check dex jars.
+			} else {
+				ctx.Errorf("module %q is of type %q which is not supported as a boot jar", name, ctx.ModuleType(apexVariant))
+			}
+		} else if strict {
+			ctx.Errorf("boot jars package check failed as it could not find module %q for apex %q", name, moduleToApex[name])
+		}
+	}
+
+	checkBootJars.Text("&& touch").Output(timestamp)
+	rule.Build(pctx, ctx, "boot_jars_package_check", "check boot jar packages")
+
+	// The check-boot-jars phony target depends on the timestamp created if the check succeeds.
+	ctx.Phony("check-boot-jars", timestamp)
+
+	// The droidcore phony target depends on the check-boot-jars phony target
+	ctx.Phony("droidcore", android.PathForPhony(ctx, "check-boot-jars"))
+}