--- a/nashorn/src/jdk/nashorn/api/scripting/NashornScriptEngine.java	Wed Jan 08 17:51:47 2014 +0530
+++ b/nashorn/src/jdk/nashorn/api/scripting/NashornScriptEngine.java	Thu Jan 09 19:23:34 2014 +0530
@@ -626,6 +626,11 @@
                 continue;
             }
 
+            // skip check for default methods - non-abstract, interface methods
+            if (! Modifier.isAbstract(method.getModifiers())) {
+                continue;
+            }
+
             Object obj = sobj.get(method.getName());
             if (! (obj instanceof ScriptFunction)) {
                 return false;

--- a/nashorn/src/jdk/nashorn/internal/runtime/linker/JavaAdapterBytecodeGenerator.java	Wed Jan 08 17:51:47 2014 +0530
+++ b/nashorn/src/jdk/nashorn/internal/runtime/linker/JavaAdapterBytecodeGenerator.java	Thu Jan 09 19:23:34 2014 +0530
@@ -651,7 +651,7 @@
             mv.athrow();
         } else {
             // If the super method is not abstract, delegate to it.
-            emitSuperCall(mv, name, methodDesc);
+            emitSuperCall(mv, method.getDeclaringClass(), name, methodDesc);
         }
 
         final Label setupGlobal = new Label();
@@ -830,12 +830,12 @@
                 SUPER_PREFIX + name, methodDesc, null, getExceptionNames(method.getExceptionTypes())));
         mv.visitCode();
 
-        emitSuperCall(mv, name, methodDesc);
+        emitSuperCall(mv, method.getDeclaringClass(), name, methodDesc);
 
         endMethod(mv);
     }
 
-    private void emitSuperCall(final InstructionAdapter mv, final String name, final String methodDesc) {
+    private void emitSuperCall(final InstructionAdapter mv, final Class owner, final String name, final String methodDesc) {
         mv.visitVarInsn(ALOAD, 0);
         int nextParam = 1;
         final Type methodType = Type.getMethodType(methodDesc);
@@ -843,7 +843,13 @@
             mv.load(nextParam, t);
             nextParam += t.getSize();
         }
-        mv.invokespecial(superClassName, name, methodDesc, false);
+
+        // default method - non-abstract, interface method
+        if (Modifier.isInterface(owner.getModifiers())) {
+            mv.invokespecial(Type.getInternalName(owner), name, methodDesc, false);
+        } else {
+            mv.invokespecial(superClassName, name, methodDesc, false);
+        }
         mv.areturn(methodType.getReturnType());
     }
 

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/nashorn/test/script/basic/JDK-8031359.js	Thu Jan 09 19:23:34 2014 +0530
@@ -0,0 +1,62 @@
+/*
+ * Copyright (c) 2010, 2014, 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.
+ */
+
+/**
+ * JDK-8031359: Invocable.getInterface() works incorrectly if interface has default methods
+ *
+ * @test
+ * @run
+ */
+
+var func = new java.util.function.Function() {
+    apply: function(arg) {
+        print("func called with " + arg);
+        return arg.toUpperCase();
+    }
+};
+
+// Function.andThen is a default method
+func.andThen(func)("hello");
+
+// Function.compose is another default method
+func.compose(new java.util.function.Function() {
+    apply: function(arg) {
+        print("compose called with " + arg);
+        return arg.charAt(0);
+    }
+})("hello");
+
+var func2 = new java.util.function.Function() {
+    apply: function(arg) {
+        print("I am func2: " + arg);
+        return arg;
+    },
+
+    andThen: function(func) {
+        print("This is my andThen!");
+        return func;
+    }
+};
+
+func2.apply("hello");
+func2.andThen(func);

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/nashorn/test/script/basic/JDK-8031359.js.EXPECTED	Thu Jan 09 19:23:34 2014 +0530
@@ -0,0 +1,6 @@
+func called with hello
+func called with HELLO
+compose called with hello
+func called with h
+I am func2: hello
+This is my andThen!

--- a/nashorn/test/src/jdk/nashorn/api/scripting/InvocableTest.java	Wed Jan 08 17:51:47 2014 +0530
+++ b/nashorn/test/src/jdk/nashorn/api/scripting/InvocableTest.java	Thu Jan 09 19:23:34 2014 +0530
@@ -26,6 +26,7 @@
 package jdk.nashorn.api.scripting;
 
 import java.util.Objects;
+import java.util.function.Function;
 import javax.script.Invocable;
 import javax.script.ScriptContext;
 import javax.script.ScriptEngine;
@@ -522,4 +523,16 @@
         Assert.assertEquals(itf.test1(42, "a", "b"), "i == 42, strings instanceof java.lang.String[] == true, strings == [a, b]");
         Assert.assertEquals(itf.test2(44, "c", "d", "e"), "arguments[0] == 44, arguments[1] instanceof java.lang.String[] == true, arguments[1] == [c, d, e]");
     }
+
+    @Test
+    @SuppressWarnings("unchecked")
+    public void defaultMethodTest() throws ScriptException {
+        final ScriptEngineManager m = new ScriptEngineManager();
+        final ScriptEngine e = m.getEngineByName("nashorn");
+        final Invocable inv = (Invocable) e;
+
+        Object obj = e.eval("({ apply: function(arg) { return arg.toUpperCase(); }})");
+        Function<String, String> func = inv.getInterface(obj, Function.class);
+        assertEquals(func.apply("hello"), "HELLO");
+    }
 }