diff --git a/android/rule_builder.go b/android/rule_builder.go
index 6226548..afb5f4e 100644
--- a/android/rule_builder.go
+++ b/android/rule_builder.go
@@ -172,7 +172,7 @@
 
 	inputs := make(map[string]Path)
 	for _, c := range r.commands {
-		for _, input := range c.inputs {
+		for _, input := range append(c.inputs, c.implicits...) {
 			inputStr := input.String()
 			if _, isOutput := outputs[inputStr]; !isOutput {
 				if _, isDepFile := depFiles[inputStr]; !isDepFile {
@@ -480,6 +480,7 @@
 type RuleBuilderCommand struct {
 	buf           strings.Builder
 	inputs        Paths
+	implicits     Paths
 	orderOnlys    Paths
 	outputs       WritablePaths
 	depFiles      WritablePaths
@@ -503,6 +504,16 @@
 	return path.String()
 }
 
+func (c *RuleBuilderCommand) addImplicit(path Path) string {
+	if c.sbox {
+		if rel, isRel, _ := maybeRelErr(c.sboxOutDir.String(), path.String()); isRel {
+			return "__SBOX_OUT_DIR__/" + rel
+		}
+	}
+	c.implicits = append(c.implicits, path)
+	return path.String()
+}
+
 func (c *RuleBuilderCommand) addOrderOnly(path Path) {
 	c.orderOnlys = append(c.orderOnlys, path)
 }
@@ -623,7 +634,7 @@
 // Implicit adds the specified input path to the dependencies returned by RuleBuilder.Inputs without modifying the
 // command line.
 func (c *RuleBuilderCommand) Implicit(path Path) *RuleBuilderCommand {
-	c.addInput(path)
+	c.addImplicit(path)
 	return c
 }
 
@@ -631,11 +642,16 @@
 // command line.
 func (c *RuleBuilderCommand) Implicits(paths Paths) *RuleBuilderCommand {
 	for _, path := range paths {
-		c.addInput(path)
+		c.addImplicit(path)
 	}
 	return c
 }
 
+// GetImplicits returns the command's implicit inputs.
+func (c *RuleBuilderCommand) GetImplicits() Paths {
+	return c.implicits
+}
+
 // OrderOnly adds the specified input path to the dependencies returned by RuleBuilder.OrderOnlys
 // without modifying the command line.
 func (c *RuleBuilderCommand) OrderOnly(path Path) *RuleBuilderCommand {
diff --git a/java/droiddoc.go b/java/droiddoc.go
index 355904d..230b1f0 100644
--- a/java/droiddoc.go
+++ b/java/droiddoc.go
@@ -121,6 +121,10 @@
 
 	// names of the output files used in args that will be generated
 	Out []string
+
+	// If set, metalava is sandboxed to only read files explicitly specified on the command
+	// line. Defaults to false.
+	Sandbox *bool
 }
 
 type ApiToCheck struct {
@@ -1434,34 +1438,18 @@
 }
 
 func metalavaCmd(ctx android.ModuleContext, rule *android.RuleBuilder, javaVersion javaVersion, srcs android.Paths,
-	srcJarList android.Path, bootclasspath, classpath classpath, sourcepaths android.Paths, implicits android.Paths) *android.RuleBuilderCommand {
+	srcJarList android.Path, bootclasspath, classpath classpath, sourcepaths android.Paths, implicitsRsp android.WritablePath, sandbox bool) *android.RuleBuilderCommand {
 	// Metalava uses lots of memory, restrict the number of metalava jobs that can run in parallel.
 	rule.HighMem()
 	cmd := rule.Command()
-
-	var implicitsRsp android.WritablePath
-	if len(implicits) > 0 {
-		implicitsRsp = android.PathForModuleOut(ctx, ctx.ModuleName()+"-"+"implicits.rsp")
-		impRule := android.NewRuleBuilder()
-		impCmd := impRule.Command()
-		// A dummy action that copies the ninja generated rsp file to a new location. This allows us to
-		// add a large number of inputs to a file without exceeding bash command length limits (which
-		// would happen if we use the WriteFile rule). The cp is needed because RuleBuilder sets the
-		// rsp file to be ${output}.rsp.
-		impCmd.Text("cp").FlagWithRspFileInputList("", implicits).Output(implicitsRsp)
-		impRule.Build(pctx, ctx, "implicitsGen", "implicits generation")
-		cmd.Implicits(implicits)
-		cmd.Implicit(implicitsRsp)
-	}
 	if ctx.Config().IsEnvTrue("RBE_METALAVA") {
 		rule.Remoteable(android.RemoteRuleSupports{RBE: true})
-		execStrategy := remoteexec.LocalExecStrategy
-		if v := ctx.Config().Getenv("RBE_METALAVA_EXEC_STRATEGY"); v != "" {
-			execStrategy = v
-		}
-		pool := "metalava"
-		if v := ctx.Config().Getenv("RBE_METALAVA_POOL"); v != "" {
-			pool = v
+		pool := ctx.Config().GetenvWithDefault("RBE_METALAVA_POOL", "metalava")
+		execStrategy := ctx.Config().GetenvWithDefault("RBE_METALAVA_EXEC_STRATEGY", remoteexec.LocalExecStrategy)
+		labels := map[string]string{"type": "compile", "lang": "java", "compiler": "metalava"}
+		if !sandbox {
+			execStrategy = remoteexec.LocalExecStrategy
+			labels["shallow"] = "true"
 		}
 		inputs := []string{android.PathForOutput(ctx, "host", ctx.Config().PrebuiltOS(), "framework", "metalava.jar").String()}
 		inputs = append(inputs, sourcepaths.Strings()...)
@@ -1469,7 +1457,7 @@
 			inputs = append(inputs, strings.Split(v, ",")...)
 		}
 		cmd.Text((&remoteexec.REParams{
-			Labels:          map[string]string{"type": "compile", "lang": "java", "compiler": "metalava", "shallow": "true"},
+			Labels:          labels,
 			ExecStrategy:    execStrategy,
 			Inputs:          inputs,
 			RSPFile:         implicitsRsp.String(),
@@ -1483,8 +1471,17 @@
 		FlagWithArg("-encoding ", "UTF-8").
 		FlagWithArg("-source ", javaVersion.String()).
 		FlagWithRspFileInputList("@", srcs).
-		FlagWithInput("@", srcJarList).
-		FlagWithOutput("--strict-input-files:warn ", android.PathForModuleOut(ctx, ctx.ModuleName()+"-"+"violations.txt"))
+		FlagWithInput("@", srcJarList)
+
+	if javaHome := ctx.Config().Getenv("ANDROID_JAVA_HOME"); javaHome != "" {
+		cmd.Implicit(android.PathForSource(ctx, javaHome))
+	}
+
+	if sandbox {
+		cmd.FlagWithOutput("--strict-input-files ", android.PathForModuleOut(ctx, ctx.ModuleName()+"-"+"violations.txt"))
+	} else {
+		cmd.FlagWithOutput("--strict-input-files:warn ", android.PathForModuleOut(ctx, ctx.ModuleName()+"-"+"violations.txt"))
+	}
 
 	if implicitsRsp != nil {
 		cmd.FlagWithArg("--strict-input-files-exempt ", "@"+implicitsRsp.String())
@@ -1534,8 +1531,12 @@
 
 	srcJarList := zipSyncCmd(ctx, rule, srcJarDir, d.Javadoc.srcJars)
 
+	implicitsRsp := android.PathForModuleOut(ctx, ctx.ModuleName()+"-"+"implicits.rsp")
+
 	cmd := metalavaCmd(ctx, rule, javaVersion, d.Javadoc.srcFiles, srcJarList,
-		deps.bootClasspath, deps.classpath, d.Javadoc.sourcepaths, d.Javadoc.implicits)
+		deps.bootClasspath, deps.classpath, d.Javadoc.sourcepaths, implicitsRsp,
+		Bool(d.Javadoc.properties.Sandbox))
+	cmd.Implicits(d.Javadoc.implicits)
 
 	d.stubsFlags(ctx, cmd, stubsDir)
 
@@ -1663,6 +1664,16 @@
 		cmd.FlagWithArg("--error-message:compatibility:released ", msg)
 	}
 
+	impRule := android.NewRuleBuilder()
+	impCmd := impRule.Command()
+	// A dummy action that copies the ninja generated rsp file to a new location. This allows us to
+	// add a large number of inputs to a file without exceeding bash command length limits (which
+	// would happen if we use the WriteFile rule). The cp is needed because RuleBuilder sets the
+	// rsp file to be ${output}.rsp.
+	impCmd.Text("cp").FlagWithRspFileInputList("", cmd.GetImplicits()).Output(implicitsRsp)
+	impRule.Build(pctx, ctx, "implicitsGen", "implicits generation")
+	cmd.Implicit(implicitsRsp)
+
 	if generateStubs {
 		rule.Command().
 			BuiltTool(ctx, "soong_zip").