diff --git a/java/java.go b/java/java.go
index e571913..1fefcab 100644
--- a/java/java.go
+++ b/java/java.go
@@ -928,6 +928,7 @@
 		}
 
 		// Make javac rule depend on the kotlinc rule
+		flags.classpath = append(flags.classpath, deps.kotlinStdlib...)
 		flags.classpath = append(flags.classpath, kotlinJar)
 
 		// Jar kotlin classes into the final jar after javac