Add missing Java throws clause for interfaces when using the %interface family of macros.

Fixes #1156.

CHANGES.current

@@ -7,6 +7,10 @@ the issue number to the end of the URL: https://github.com/swig/swig/issues/
 Version 4.0.0 (in progress)
 ===========================
 
+2018-01-12: wsfulton
+            [Java] Fix issue #1156. Add missing throws clause for interfaces when using the
+            %interface family of macros.
+
 2018-01-05: wsfulton
             Fix default arguments using expressions containing -> syntax error. Problem reported on
             swig-user mailing list.

Examples/test-suite/java/java_throws_runme.java

@@ -93,6 +93,28 @@ public class java_throws_runme {
       if (!pass)
         throw new RuntimeException("Test 6 failed");
 
+      // Interface function
+      pass = false;
+      try {
+        InterfaceTestImpl iti = new InterfaceTestImpl();
+        iti.imethod(true);
+      }
+      catch (MyException e) { pass = true; }
+
+      if (!pass)
+        throw new RuntimeException("Test interface 1 failed");
+
+      pass = false;
+      try {
+        InterfaceTestImpl iti = new InterfaceTestImpl();
+        iti.imethod(false);
+        pass = true;
+      }
+      catch (MyException e) { pass = false; }
+
+      if (!pass)
+        throw new RuntimeException("Test interface 2 failed");
+
       // Global function
       pass = false;
       try {

Examples/test-suite/java_throws.i

@@ -135,6 +135,23 @@ JAVAEXCEPTION(FeatureTest::staticMethod)
     };
 %}
 
+%include <swiginterface.i>
+%interface_impl(InterfaceTest);
+JAVAEXCEPTION(imethod)
+
+%inline %{
+    struct InterfaceTest {
+        virtual void imethod(bool raise) = 0;
+    };
+
+    struct InterfaceTestImpl : InterfaceTest {
+        void imethod(bool raise) {
+            if (raise)
+                throw MyException("raise message");
+        }
+    };
+%}
+
 // Mixing except feature and typemaps when both generate a class for the throws clause
 %typemap(in, throws="ClassNotFoundException") int both { 
     $1 = (int)$input;

Source/Modules/java.cxx

@@ -2544,8 +2544,6 @@ public:
 
     Printf(imcall, ")");
     Printf(function_code, ")");
-    if (is_interface)
-      Printf(interface_class_code, ");\n");
 
     // Transform return type used in JNI function (in intermediary class) to type used in Java wrapper function (in proxy class)
     if ((tm = Swig_typemap_lookup("javaout", n, "", 0))) {
@@ -2603,6 +2601,11 @@ public:
       Swig_warning(WARN_JAVA_TYPEMAP_JAVAOUT_UNDEF, input_file, line_number, "No javaout typemap defined for %s\n", SwigType_str(t, 0));
     }
 
+    if (is_interface) {
+      Printf(interface_class_code, ")");
+      generateThrowsClause(n, interface_class_code);
+      Printf(interface_class_code, ";\n");
+    }
     generateThrowsClause(n, function_code);
     Printf(function_code, " %s\n\n", tm ? (const String *) tm : empty_string);
     Printv(proxy_class_code, function_code, NIL);