start implementation of benchmark things

benchmark/src/main/java/org/capnproto/benchmark/Benchmark.java

@@ -0,0 +1,7 @@
+package org.capnproto.benchmark;
+
+public class Benchmark {
+    public static void main(String[] args) {
+        System.out.println("hello world");
+    }
+}

benchmark/src/main/java/org/capnproto/benchmark/Common.java

@@ -0,0 +1,19 @@
+package org.capnproto.benchmark;
+
+public class Common {
+    public static class FastRand {
+        public static final int a = 1664525;
+        public static final int c = 1013904223;
+        public int state;
+
+        public FastRand() {
+            this.state = 1013904223;
+        }
+
+        public int next_int() {
+            this.state = this.a * this.state + c;
+            return this.state;
+        }
+    }
+
+}

benchmark/src/main/schema/carsales.capnp

@@ -28,7 +28,7 @@ $Cxx.namespace("capnp::benchmark::capnp");
 
 using Java = import "/java_support/java.capnp";
 $Java.package("org.capnproto.benchmark");
-$Java.outerClassname("Carsales");
+$Java.outerClassname("CarSalesSchema");
 
 struct ParkingLot {
   cars@0: List(Car);