--- a/src/jdk.jdeps/share/classes/com/sun/tools/jdeps/JdepsConfiguration.java	Fri Jun 15 12:48:19 2018 -0700
+++ b/src/jdk.jdeps/share/classes/com/sun/tools/jdeps/JdepsConfiguration.java	Fri Jun 15 13:08:32 2018 -0700
@@ -347,7 +347,7 @@
                 this.root = null;
                 this.systemModules = Collections.emptyMap();
             } else {
-                if (Files.isRegularFile(Paths.get(javaHome, "lib", "modules")))
+                if (!Files.isRegularFile(Paths.get(javaHome, "lib", "modules")))
                     throw new IllegalArgumentException("Invalid java.home: " + javaHome);
 
                 // alternate java.home

--- a/test/langtools/tools/jdeps/Options.java	Fri Jun 15 12:48:19 2018 -0700
+++ b/test/langtools/tools/jdeps/Options.java	Fri Jun 15 13:08:32 2018 -0700
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2016, 2018, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -23,7 +23,7 @@
 
 /*
  * @test
- * @bug 8168386
+ * @bug 8168386 8205116
  * @summary Test option validation
  * @modules jdk.jdeps
  * @library lib
@@ -89,4 +89,18 @@
         assertTrue(jdeps.run(true) != 0);
         return jdeps;
     }
+
+    @Test
+    public void testSystemOption() {
+        JdepsRunner jdeps;
+
+        // valid path
+        jdeps = new JdepsRunner("--check", "java.base", "--system", System.getProperty("java.home"));
+        assertTrue(jdeps.run(true) == 0);
+
+        // invalid path
+        jdeps = new JdepsRunner("--check", "java.base", "--system", "bad");
+        assertTrue(jdeps.run(true) != 0);
+        jdeps.outputContains("invalid path: bad");
+    }
 }