diff --git a/java/java.go b/java/java.go
index dbfad02..f0eeb29 100644
--- a/java/java.go
+++ b/java/java.go
@@ -2505,6 +2505,11 @@
 }
 
 func (j *Test) GenerateAndroidBuildActions(ctx android.ModuleContext) {
+	if j.testProperties.Test_options.Unit_test == nil && ctx.Host() {
+		// TODO(b/): Clean temporary heuristic to avoid unexpected onboarding.
+		defaultUnitTest := !inList("tradefed", j.properties.Static_libs) && !inList("tradefed", j.properties.Libs) && !inList("cts", j.testProperties.Test_suites) && !inList("robolectric-host-android_all", j.properties.Static_libs) && !inList("robolectric-host-android_all", j.properties.Libs)
+		j.testProperties.Test_options.Unit_test = proptools.BoolPtr(defaultUnitTest)
+	}
 	j.testConfig = tradefed.AutoGenJavaTestConfig(ctx, j.testProperties.Test_config, j.testProperties.Test_config_template,
 		j.testProperties.Test_suites, j.testProperties.Auto_gen_config, j.testProperties.Test_options.Unit_test)
 
@@ -2665,6 +2670,7 @@
 	module.Module.properties.Installable = proptools.BoolPtr(true)
 
 	InitJavaModuleMultiTargets(module, android.HostSupported)
+
 	return module
 }