diff --git a/java/java.go b/java/java.go
index 71c1b33..ca63782 100644
--- a/java/java.go
+++ b/java/java.go
@@ -1283,6 +1283,10 @@
 
 		// Save away the `deapexer` module on which this depends, if any.
 		if tag == android.DeapexerTag {
+			if deapexerModule != nil {
+				ctx.ModuleErrorf("Ambiguous duplicate deapexer module dependencies %q and %q",
+					deapexerModule.Name(), module.Name())
+			}
 			deapexerModule = module
 		}
 	})