diff --git a/compiler/src/main/cpp/capnpc-java.c++ b/compiler/src/main/cpp/capnpc-java.c++
index 17e37bf..a6496ab 100644
--- a/compiler/src/main/cpp/capnpc-java.c++
+++ b/compiler/src/main/cpp/capnpc-java.c++
@@ -1792,10 +1792,10 @@ private:
     }
 
     if (packageName.size() == 0) {
-      context.exitError(kj::str(displayName, ": must provide a Java package name."));
+      context.exitError(kj::str(displayName, ": no Java package name found. See java.capnp."));
     }
     if (outerClassname.size() == 0) {
-      context.exitError(kj::str(displayName, ": must provide a Java outer classname."));
+      context.exitError(kj::str(displayName, ": no Java outer classname found. See java.capnp."));
     }
 
     auto nodeTexts = KJ_MAP(nested, node.getNestedNodes()) {
diff --git a/compiler/src/main/schema/capnp/java.capnp b/compiler/src/main/schema/capnp/java.capnp
index 5c70776..cddf6eb 100644
--- a/compiler/src/main/schema/capnp/java.capnp
+++ b/compiler/src/main/schema/capnp/java.capnp
@@ -1,5 +1,28 @@
+# Copyright (c) 2013-2015 Sandstorm Development Group, Inc. and contributors
+# Licensed under the MIT License:
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+
 @0xc5f1af96651f70ea;
 
 annotation package @0x9ee4c8f803b3b596 (file) : Text;
+# Name of the package, such as "org.example.foo", in which the generated code will reside.
 
-annotation outerClassname @0x9b066bb4881f7cd3 (file) : Text;
\ No newline at end of file
+annotation outerClassname @0x9b066bb4881f7cd3 (file) : Text;
+# Name of the outer class that will wrap the generated code.