diff --git a/java/droiddoc.go b/java/droiddoc.go
index 6b39314..fd4b90d 100644
--- a/java/droiddoc.go
+++ b/java/droiddoc.go
@@ -547,10 +547,10 @@
 		case bootClasspathTag:
 			if dep, ok := module.(Dependency); ok {
 				deps.bootClasspath = append(deps.bootClasspath, dep.ImplementationJars()...)
-			} else if sm, ok := module.(*SystemModules); ok {
+			} else if sm, ok := module.(SystemModulesProvider); ok {
 				// A system modules dependency has been added to the bootclasspath
 				// so add its libs to the bootclasspath.
-				deps.bootClasspath = append(deps.bootClasspath, sm.headerJars...)
+				deps.bootClasspath = append(deps.bootClasspath, sm.HeaderJars()...)
 			} else {
 				panic(fmt.Errorf("unknown dependency %q for %q", otherName, ctx.ModuleName()))
 			}
@@ -578,11 +578,9 @@
 			if deps.systemModules != nil {
 				panic("Found two system module dependencies")
 			}
-			sm := module.(*SystemModules)
-			if sm.outputDir == nil && len(sm.outputDeps) == 0 {
-				panic("Missing directory for system module dependency")
-			}
-			deps.systemModules = &systemModules{sm.outputDir, sm.outputDeps}
+			sm := module.(SystemModulesProvider)
+			outputDir, outputDeps := sm.OutputDirAndDeps()
+			deps.systemModules = &systemModules{outputDir, outputDeps}
 		}
 	})
 	// do not pass exclude_srcs directly when expanding srcFiles since exclude_srcs
diff --git a/java/java.go b/java/java.go
index c3e2c96..462dba8 100644
--- a/java/java.go
+++ b/java/java.go
@@ -1031,18 +1031,16 @@
 			case bootClasspathTag:
 				// If a system modules dependency has been added to the bootclasspath
 				// then add its libs to the bootclasspath.
-				sm := module.(*SystemModules)
-				deps.bootClasspath = append(deps.bootClasspath, sm.headerJars...)
+				sm := module.(SystemModulesProvider)
+				deps.bootClasspath = append(deps.bootClasspath, sm.HeaderJars()...)
 
 			case systemModulesTag:
 				if deps.systemModules != nil {
 					panic("Found two system module dependencies")
 				}
-				sm := module.(*SystemModules)
-				if sm.outputDir == nil || len(sm.outputDeps) == 0 {
-					panic("Missing directory for system module dependency")
-				}
-				deps.systemModules = &systemModules{sm.outputDir, sm.outputDeps}
+				sm := module.(SystemModulesProvider)
+				outputDir, outputDeps := sm.OutputDirAndDeps()
+				deps.systemModules = &systemModules{outputDir, outputDeps}
 			}
 		}
 	})
diff --git a/java/java_test.go b/java/java_test.go
index a2226b5..52b3bc0 100644
--- a/java/java_test.go
+++ b/java/java_test.go
@@ -982,6 +982,65 @@
 	}
 }
 
+func TestDroidstubsWithSystemModules(t *testing.T) {
+	ctx, _ := testJava(t, `
+		droidstubs {
+		    name: "stubs-source-system-modules",
+		    srcs: [
+		        "bar-doc/*.java",
+		    ],
+				sdk_version: "none",
+				system_modules: "source-system-modules",
+		}
+
+		java_library {
+				name: "source-jar",
+		    srcs: [
+		        "a.java",
+		    ],
+		}
+
+		java_system_modules {
+				name: "source-system-modules",
+				libs: ["source-jar"],
+		}
+
+		droidstubs {
+		    name: "stubs-prebuilt-system-modules",
+		    srcs: [
+		        "bar-doc/*.java",
+		    ],
+				sdk_version: "none",
+				system_modules: "prebuilt-system-modules",
+		}
+
+		java_import {
+				name: "prebuilt-jar",
+				jars: ["a.jar"],
+		}
+
+		java_system_modules_import {
+				name: "prebuilt-system-modules",
+				libs: ["prebuilt-jar"],
+		}
+		`)
+
+	checkSystemModulesUseByDroidstubs(t, ctx, "stubs-source-system-modules", "source-jar.jar")
+
+	checkSystemModulesUseByDroidstubs(t, ctx, "stubs-prebuilt-system-modules", "prebuilt-jar.jar")
+}
+
+func checkSystemModulesUseByDroidstubs(t *testing.T, ctx *android.TestContext, moduleName string, systemJar string) {
+	metalavaRule := ctx.ModuleForTests(moduleName, "android_common").Rule("metalava")
+	var systemJars []string
+	for _, i := range metalavaRule.Implicits {
+		systemJars = append(systemJars, i.Base())
+	}
+	if len(systemJars) != 1 || systemJars[0] != systemJar {
+		t.Errorf("inputs of %q must be []string{%q}, but was %#v.", moduleName, systemJar, systemJars)
+	}
+}
+
 func TestJarGenrules(t *testing.T) {
 	ctx, _ := testJava(t, `
 		java_library {
@@ -1377,3 +1436,59 @@
 		}
 	}
 }
+
+func TestJavaLibraryWithSystemModules(t *testing.T) {
+	ctx, _ := testJava(t, `
+		java_library {
+		    name: "lib-with-source-system-modules",
+		    srcs: [
+		        "a.java",
+		    ],
+				sdk_version: "none",
+				system_modules: "source-system-modules",
+		}
+
+		java_library {
+				name: "source-jar",
+		    srcs: [
+		        "a.java",
+		    ],
+		}
+
+		java_system_modules {
+				name: "source-system-modules",
+				libs: ["source-jar"],
+		}
+
+		java_library {
+		    name: "lib-with-prebuilt-system-modules",
+		    srcs: [
+		        "a.java",
+		    ],
+				sdk_version: "none",
+				system_modules: "prebuilt-system-modules",
+		}
+
+		java_import {
+				name: "prebuilt-jar",
+				jars: ["a.jar"],
+		}
+
+		java_system_modules_import {
+				name: "prebuilt-system-modules",
+				libs: ["prebuilt-jar"],
+		}
+		`)
+
+	checkBootClasspathForSystemModule(t, ctx, "lib-with-source-system-modules", "/source-jar.jar")
+
+	checkBootClasspathForSystemModule(t, ctx, "lib-with-prebuilt-system-modules", "/prebuilt-jar.jar")
+}
+
+func checkBootClasspathForSystemModule(t *testing.T, ctx *android.TestContext, moduleName string, expectedSuffix string) {
+	javacRule := ctx.ModuleForTests(moduleName, "android_common").Rule("javac")
+	bootClasspath := javacRule.Args["bootClasspath"]
+	if strings.HasPrefix(bootClasspath, "--system ") && strings.HasSuffix(bootClasspath, expectedSuffix) {
+		t.Errorf("bootclasspath of %q must start with --system and end with %q, but was %#v.", moduleName, expectedSuffix, bootClasspath)
+	}
+}
diff --git a/java/system_modules.go b/java/system_modules.go
index 731503f..47de6e3 100644
--- a/java/system_modules.go
+++ b/java/system_modules.go
@@ -117,6 +117,15 @@
 	return module
 }
 
+type SystemModulesProvider interface {
+	HeaderJars() android.Paths
+	OutputDirAndDeps() (android.Path, android.Paths)
+}
+
+var _ SystemModulesProvider = (*SystemModules)(nil)
+
+var _ SystemModulesProvider = (*systemModulesImport)(nil)
+
 type SystemModules struct {
 	android.ModuleBase
 	android.DefaultableModuleBase
@@ -136,6 +145,17 @@
 	Libs []string
 }
 
+func (system *SystemModules) HeaderJars() android.Paths {
+	return system.headerJars
+}
+
+func (system *SystemModules) OutputDirAndDeps() (android.Path, android.Paths) {
+	if system.outputDir == nil || len(system.outputDeps) == 0 {
+		panic("Missing directory for system module dependency")
+	}
+	return system.outputDir, system.outputDeps
+}
+
 func (system *SystemModules) GenerateAndroidBuildActions(ctx android.ModuleContext) {
 	var jars android.Paths