--- a/src/jdk.compiler/share/classes/com/sun/tools/javac/api/JavacTool.java	Mon Dec 11 08:20:05 2017 +0100
+++ b/src/jdk.compiler/share/classes/com/sun/tools/javac/api/JavacTool.java	Fri Dec 08 16:28:14 2017 +0100
@@ -219,7 +219,7 @@
         Set<Option> recognizedOptions = Option.getJavacToolOptions();
         for (Option o : recognizedOptions) {
             if (o.matches(option)) {
-                return o.hasArg() ? 1 : 0;
+                return o.hasSeparateArg() ? 1 : 0;
             }
         }
         return -1;

--- a/src/jdk.compiler/share/classes/com/sun/tools/javac/main/Option.java	Mon Dec 11 08:20:05 2017 +0100
+++ b/src/jdk.compiler/share/classes/com/sun/tools/javac/main/Option.java	Fri Dec 08 16:28:14 2017 +0100
@@ -1025,6 +1025,11 @@
         return (argKind != ArgKind.NONE);
     }
 
+    public boolean hasSeparateArg() {
+        return getArgKind() == ArgKind.REQUIRED &&
+               !primaryName.endsWith(":") && !primaryName.endsWith("=");
+    }
+
     public boolean matches(String option) {
         for (String name: names) {
             if (matches(option, name))

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/langtools/tools/javac/options/IsSupportedOptionTest.java	Fri Dec 08 16:28:14 2017 +0100
@@ -0,0 +1,77 @@
+/*
+ * Copyright (c) 2017, 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
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 8189782
+ * @summary Test for isSupportedOption
+ * @modules java.compiler
+ *          jdk.compiler
+ * @run main IsSupportedOptionTest
+ */
+
+import javax.tools.JavaCompiler;
+import javax.tools.ToolProvider;
+
+/**
+ * Tests for JavaCompiler.isSupportedOption method.
+ */
+public class IsSupportedOptionTest {
+    public static void main(String... args) throws Exception {
+        new IsSupportedOptionTest().run();
+    }
+
+    public void run() throws Exception {
+        JavaCompiler tool = ToolProvider.getSystemJavaCompiler();
+        check(tool, "-source", 1);
+        check(tool, "--add-modules", 1);
+        check(tool, "-verbose", 0);
+        check(tool, "-proc:none", 0);
+        check(tool, "-Xlint", 0);
+        check(tool, "-Xlint:unchecked", 0);
+        check(tool, "-Xdoclint", 0);
+        check(tool, "-Xdoclint:stats", 0);
+        check(tool, "-Xdoclint/package:foo", 0);
+        check(tool, "--debug:any", 0);
+        check(tool, "-g", 0);
+        check(tool, "-g:vars", 0);
+        check(tool, "-g:none", 0);
+        check(tool, "-ZZZ", -1);
+        check(tool, "-Afoobar", 0);
+
+        try {
+            check(tool, null, -1);
+            throw new AssertionError("null was accepted without exception");
+        } catch (NullPointerException e) {
+        }
+    }
+
+    private void check(JavaCompiler tool, String option, int numArgs) {
+        System.err.println("check " + option);
+        int n = tool.isSupportedOption(option);
+        if (n != numArgs) {
+            throw new AssertionError("unexpected result for option: " + option + ": " + n);
+        }
+    }
+}
+