func sortedMethodNames(typ *types.Interface) []string {
	n := typ.NumMethods()
	list := make([]string, n)
	for i := range list {
		list[i] = typ.Method(i).Name()
	}
	sort.Strings(list)
	return list
}

func (p *exporter) iface(t *types.Interface) {
	// TODO(gri): enable importer to load embedded interfaces,
	// then emit Embeddeds and ExplicitMethods separately here.
	p.int(0)

	n := t.NumMethods()
	if trace && n > 0 {
		p.tracef("methods {>\n")
		defer p.tracef("<\n} ")
	}
	p.int(n)
	for i := 0; i < n; i++ {
		if trace && i > 0 {
			p.tracef("\n")
		}
		p.method(t.Method(i))
	}
}

func (c *converter) convertInterface(v *gotypes.Interface) *types.Interface {
	if v == nil {
		return nil
	}
	if v, ok := c.converted[v]; ok {
		return v.(*types.Interface)
	}
	ret := types.NewInterface(nil, nil)
	c.converted[v] = ret
	for i := 0; i < v.NumExplicitMethods(); i++ {
		ret.AddMethod(c.convertFunc(v.ExplicitMethod(i)))
	}
	for i := 0; i < v.NumEmbeddeds(); i++ {
		ret.AddEmbedded(c.convertNamed(v.Embedded(i)))
	}
	c.ifaces = append(c.ifaces, ret)
	return ret
}

func implements(t types.Type, interfac *types.Interface, pkg *types.Package) bool {
	if interfac == nil || t == nil || interfac.Empty() {
		return false
	}
	if types.Implements(t, interfac) {
		return true
	}
	//For some reason, interfaces that comes
	//already built in (not from sources) are
	//not working with types.Implements method
	for i := 0; i < interfac.NumMethods(); i++ {
		m := interfac.Method(i)
		obj, _, _ := types.LookupFieldOrMethod(t, true, pkg, m.Name())
		if obj == nil {
			util.Debug("method %s not found in type %v", m.Name(), t)
			return false
		}
	}
	return true
}

func (g *javaGen) genInterfaceStub(o *types.TypeName, m *types.Interface) {
	g.Printf("public static abstract class Stub implements %s {\n", o.Name())
	g.Indent()

	g.Printf("static final String DESCRIPTOR = \"go.%s.%s\";\n\n", g.pkg.Name(), o.Name())
	g.Printf("private final go.Seq.Ref ref;\n")
	g.Printf("public Stub() {\n    ref = go.Seq.createRef(this);\n}\n\n")
	g.Printf("public go.Seq.Ref ref() { return ref; }\n\n")

	g.Printf("public void call(int code, go.Seq in, go.Seq out) {\n")
	g.Indent()
	g.Printf("switch (code) {\n")

	for i := 0; i < m.NumMethods(); i++ {
		f := m.Method(i)
		g.Printf("case Proxy.CALL_%s: {\n", f.Name())
		g.Indent()

		sig := f.Type().(*types.Signature)
		params := sig.Params()
		for i := 0; i < params.Len(); i++ {
			p := sig.Params().At(i)
			jt := g.javaType(p.Type())
			g.Printf("%s param_%s;\n", jt, paramName(params, i))
			g.genRead("param_"+paramName(params, i), "in", p.Type())
		}

		res := sig.Results()
		var returnsError bool
		var numRes = res.Len()
		if (res.Len() == 1 && isErrorType(res.At(0).Type())) ||
			(res.Len() == 2 && isErrorType(res.At(1).Type())) {
			numRes -= 1
			returnsError = true
		}

		if returnsError {
			g.Printf("try {\n")
			g.Indent()
		}

		if numRes > 0 {
			g.Printf("%s result = ", g.javaType(res.At(0).Type()))
		}

		g.Printf("this.%s(", f.Name())
		for i := 0; i < params.Len(); i++ {
			if i > 0 {
				g.Printf(", ")
			}
			g.Printf("param_%s", paramName(params, i))
		}
		g.Printf(");\n")

		if numRes > 0 {
			g.Printf("out.write%s;\n", seqWrite(res.At(0).Type(), "result"))
		}
		if returnsError {
			g.Printf("out.writeString(null);\n")
			g.Outdent()
			g.Printf("} catch (Exception e) {\n")
			g.Indent()
			if numRes > 0 {
				resTyp := res.At(0).Type()
				g.Printf("%s result = %s;\n", g.javaType(resTyp), g.javaTypeDefault(resTyp))
				g.Printf("out.write%s;\n", seqWrite(resTyp, "result"))
			}
			g.Printf("out.writeString(e.getMessage());\n")
			g.Outdent()
			g.Printf("}\n")
		}
		g.Printf("return;\n")
		g.Outdent()
		g.Printf("}\n")
	}

	g.Printf("default:\n    throw new RuntimeException(\"unknown code: \"+ code);\n")
	g.Printf("}\n")
	g.Outdent()
	g.Printf("}\n")

	g.Outdent()
	g.Printf("}\n\n")
}