RE: jruby#2635 Fix support of const_get with leading colons

core/src/main/java/org/jruby/RubyModule.java

@@ -3039,7 +3039,10 @@ public IRubyObject const_get_2_0(ThreadContext context, IRubyObject[] args) {
 
         RubyModule mod = this;
 
-        if (symbol.startsWith("::")) mod = runtime.getObject();
+        if (symbol.startsWith("::")) {
+          mod = runtime.getObject();
+          symbol = symbol.substring(2);
+        }
 
         int sep;
         while((sep = symbol.indexOf("::")) != -1) {

spec/regression/GH-2635_const_get_with_leading_colons_spec.rb

@@ -0,0 +1,19 @@
+describe ".const_get" do
+
+  module Example
+    class Foo
+      Bar = "bar"
+    end
+  end
+
+  context "with leading colons" do
+    it "finds the toplevel constant" do
+      Object.const_get("::Example").should == Example
+    end
+
+    it "works with arbitrarily nested constants" do
+      Object.const_get("::Example::Foo::Bar").should == "bar"
+    end
+  end
+
+end