Add length getter to ListWrapper.

pkg/analyzer_experimental/lib/src/generated/java_core.dart

 library java.core;
 
 import "dart:math" as math;
 import "dart:uri";
 import "dart:collection" show ListBase;
 
 class JavaSystem {
   static int currentTimeMillis() {
     return (new DateTime.now()).millisecondsSinceEpoch;
   }
@@ skipping 259 matching lines @@
   }
 
   void operator []=(int index, E value) {
     elements[index] = value;
   }
 
   void set length(int newLength) {
     elements.length = newLength;
   }
 
+  int get length => elements.length;
+
   void add(E value) {
     elements.add(value);
   }
 
   void addLast(E value) {
     elements.add(value);
   }
 
   void addAll(Iterable<E> iterable) {
     elements.addAll(iterable);
@@ skipping 148 matching lines @@
       }
     } else if (sb.length > newLength) {
       var s = sb.toString().substring(0, newLength);
       sb = new StringBuffer(s);
     }
   }
   void clear() {
     sb = new StringBuffer();
   }
 }