diff --git a/java/droiddoc.go b/java/droiddoc.go
index 9eaa1b6..5deac5e 100644
--- a/java/droiddoc.go
+++ b/java/droiddoc.go
@@ -17,7 +17,6 @@
 import (
 	"fmt"
 	"path/filepath"
-	"runtime"
 	"strings"
 
 	"github.com/google/blueprint/proptools"
@@ -687,13 +686,6 @@
 }
 
 func (d *Droiddoc) doclavaDocsFlags(ctx android.ModuleContext, cmd *android.RuleBuilderCommand, docletPath classpath) {
-	var date string
-	if runtime.GOOS == "darwin" {
-		date = `date -r`
-	} else {
-		date = `date -d @`
-	}
-
 	// Droiddoc always gets "-source 1.8" because it doesn't support 1.9 sources.  For modules with 1.9
 	// sources, droiddoc will get sources produced by metalava which will have already stripped out the
 	// 1.9 language features.
@@ -704,7 +696,7 @@
 		FlagWithArg("-doclet ", "com.google.doclava.Doclava").
 		FlagWithInputList("-docletpath ", docletPath.Paths(), ":").
 		FlagWithArg("-hdf page.build ", ctx.Config().BuildId()+"-"+ctx.Config().BuildNumberFromFile()).
-		FlagWithArg("-hdf page.now ", `"$(`+date+`$(cat `+ctx.Config().Getenv("BUILD_DATETIME_FILE")+`) "+%d %b %Y %k:%M")" `)
+		FlagWithArg("-hdf page.now ", `"$(date -d @$(cat `+ctx.Config().Getenv("BUILD_DATETIME_FILE")+`) "+%d %b %Y %k:%M")" `)
 
 	if String(d.properties.Custom_template) == "" {
 		// TODO: This is almost always droiddoc-templates-sdk