diff --git a/benchmark/src/main/java/org/capnproto/benchmark/Common.java b/benchmark/src/main/java/org/capnproto/benchmark/Common.java
index 8bcdd89..f9f6ce1 100644
--- a/benchmark/src/main/java/org/capnproto/benchmark/Common.java
+++ b/benchmark/src/main/java/org/capnproto/benchmark/Common.java
@@ -26,4 +26,20 @@ public class Common {
         }
     }
 
+    public static int div(int a, int b){
+        if (b == 0) return 0x7fffffff;
+        if (a == 0x80000000 && b == -1) {
+            return 0x7fffffff;
+        }
+        return a / b;
+    }
+
+    public static int modulus(int a, int b) {
+        if (b == 0) return 0x7fffffff;
+        if (a == 0x80000000 && b == -1) {
+            return 0x7fffffff;
+        }
+        return a % b;
+    }
+
 }
diff --git a/benchmark/src/main/java/org/capnproto/benchmark/Eval.java b/benchmark/src/main/java/org/capnproto/benchmark/Eval.java
new file mode 100644
index 0000000..7112e31
--- /dev/null
+++ b/benchmark/src/main/java/org/capnproto/benchmark/Eval.java
@@ -0,0 +1,70 @@
+package org.capnproto.benchmark;
+
+import org.capnproto.MessageBuilder;
+import org.capnproto.StructList;
+import org.capnproto.Text;
+import org.capnproto.benchmark.EvalSchema.*;
+
+public class Eval {
+    public static int makeExpression(Common.FastRand rng, Expression.Builder exp, int depth) {
+        exp.setOp(Operation.values()[rng.nextLessThan(Operation.values().length)]);
+
+        int left = 0;
+        if (rng.nextLessThan(8) < depth) {
+            int tmp = rng.nextLessThan(128) + 1;
+            exp.getLeft().setValue(tmp);
+            left = tmp;
+        } else {
+            left = makeExpression(rng, exp.getLeft().initExpression(), depth + 1);
+        }
+
+        int right = 0;
+        if (rng.nextLessThan(8) < depth) {
+            int tmp = rng.nextLessThan(128) + 1;
+            exp.getRight().setValue(tmp);
+            right = tmp;
+        } else {
+            right = makeExpression(rng, exp.getRight().initExpression(), depth + 1);
+        }
+
+        switch (exp.getOp()) {
+        case ADD: return left + right;
+        case SUBTRACT: return left - right;
+        case MULTIPLY: return left * right;
+        case DIVIDE: return Common.div(left, right);
+        case MODULUS: return Common.modulus(left, right);
+        default:
+            throw new Error("impossible");
+        }
+    }
+
+    public static int evaluateExpression(Expression.Reader exp) {
+        int left = 0, right = 0;
+
+        switch (exp.getLeft().which()) {
+        case VALUE:
+            left = exp.getLeft().getValue();
+            break;
+        case EXPRESSION:
+            left = evaluateExpression(exp.getLeft().getExpression());
+        }
+
+        switch (exp.getRight().which()) {
+        case VALUE:
+            right = exp.getRight().getValue();
+            break;
+        case EXPRESSION:
+            right = evaluateExpression(exp.getRight().getExpression());
+        }
+
+        switch (exp.getOp()) {
+        case ADD: return left + right;
+        case SUBTRACT: return left - right;
+        case MULTIPLY: return left * right;
+        case DIVIDE: return Common.div(left, right);
+        case MODULUS: return Common.modulus(left, right);
+        default:
+            throw new Error("impossible");
+        }
+    }
+}
diff --git a/benchmark/src/main/schema/catrank.capnp b/benchmark/src/main/schema/catrank.capnp
index 08ecc22..f30e6c3 100644
--- a/benchmark/src/main/schema/catrank.capnp
+++ b/benchmark/src/main/schema/catrank.capnp
@@ -28,7 +28,7 @@ $Cxx.namespace("capnp::benchmark::capnp");
 
 using Java = import "/java_support/java.capnp";
 $Java.package("org.capnproto.benchmark");
-$Java.outerClassname("Catrank");
+$Java.outerClassname("CatrankSchema");
 
 struct SearchResultList {
   results@0: List(SearchResult);
diff --git a/benchmark/src/main/schema/eval.capnp b/benchmark/src/main/schema/eval.capnp
index 1fa8948..bebdcb4 100644
--- a/benchmark/src/main/schema/eval.capnp
+++ b/benchmark/src/main/schema/eval.capnp
@@ -28,7 +28,7 @@ $Cxx.namespace("capnp::benchmark::capnp");
 
 using Java = import "/java_support/java.capnp";
 $Java.package("org.capnproto.benchmark");
-$Java.outerClassname("Eval");
+$Java.outerClassname("EvalSchema");
 
 enum Operation {
   add @0;