Turn Java Security Manager Off In Google App Engine SDK

For some reasons you might want to turn Java Security Management off for Google Appengine Development Environment.

I need this for properly handling of Tapestry5 error page. With Java SecurityManager enabled it produced the following errors:

Could not initialize class org.apache.tapestry5.corelib.components.Loop

java.lang.NoClassDefFoundError: Could not initialize class
 org.apache.tapestry5.corelib.components.Loop

java.lang.NoClassDefFoundError:
 org/apache/tapestry5/corelib/components/Loop$1

To turn it off, you should replace two classes in SDK, that are responsible to installing Security Manager.

1. Close all Eclipse instances


2. Locate appengine-tools-api.jar: %YOUR_ECLIPSE_FOLDER%\plugins\com.google.appengine.eclipse.sdkbundle_1.2.2.v200907291526\appengine-java-sdk-1.2.2\lib\appengine-tools-api.jar


3. Replace original classes com\google\appengine\tools\development\DevAppServerFactory$CustomSecurityManager.class and com\google\apphosting\utils\security\SecurityManagerInstaller.class with ones provided below (you may want to do a backup first)

Thats all. Now after starting App Engine project in eclipse you should see the following output in console:

Skip install SecurityManager
Create dummy CustomSecurityManager
The server is running at http://localhost:8080/

Just keep in mind that original App Engine cloud still have those Security Managers installed.

FYI here is the sources of those classes:

DevAppServerFactory.java

package com.google.appengine.tools.development;

import java.security.Permission;

public class DevAppServerFactory {

    public static class CustomSecurityManager extends SecurityManager {

        @Override
        public void checkPermission(Permission perm) {
            //    Do nothing
        }
        
        public CustomSecurityManager(DevAppServer devAppServer) {
            System.out.println("Create dummy CustomSecurityManager");
        }
        
    }
    
}

SecurityManagerInstaller.java

package com.google.apphosting.utils.security;

import java.net.URL;

public class SecurityManagerInstaller {

    public static void install(URL... urls) {
        System.out.println("Skip install SecurityManager");
    }
    
}

Download Google App Engine/Java 1.2.2 Security Manager patch here (3 KB)

.Net Collections Lookup Performance

using System;
using System.Collections.Generic;
using System.Linq;
using NUnit.Framework;

namespace TechNoir.NorCal.BL.Tests
{
    [TestFixture]
    public class PerformanceTests
    {
        [Test]
        public void CompareLookupSpeed()
        {
            bool warmUp = true;

            for (int j = 1; j <= 10; j++)
            {
                int n = j * 1000;

                Console.WriteLine("\nTest {0}; n = {1}\n", j, n);

                List<int> list;
                Dictionary<int, object> dictionary;
                List<int> sortedList;
                IQueryable<int> queryable;

                PrepareTestData(n, 
                    out list, out dictionary, out sortedList, out queryable);


                DateTime start = DateTime.Now;
                foreach (int item in list)
                {
                    Assert.That(dictionary.ContainsKey(item));
                }
                DateTime end = DateTime.Now;

                Console.WriteLine("IDictionary.ContainsKey : " 
                    + (end - start).TotalMilliseconds);


                start = DateTime.Now;
                foreach (int item in list)
                {
                    Assert.That(sortedList.BinarySearch(item) != -1);
                }
                end = DateTime.Now;

                Console.WriteLine("List.BinarySearch       : " 
                    + (end - start).TotalMilliseconds);


                start = DateTime.Now;
                foreach (var item in list)
                {
                    Assert.That(list.Contains(item));
                }
                end = DateTime.Now;

                Console.WriteLine("List.Contains           : " 
                    + (end - start).TotalMilliseconds);


                start = DateTime.Now;
                if (j <= 3)
                {
                    foreach (int item in list)
                    {
                        int localItem = item;
                        Assert.That(queryable.Any(i => i == localItem));
                    }
                }
                end = DateTime.Now;

                Console.WriteLine("IQueryable.Any          : " 
                    + (end - start).TotalMilliseconds);


                if (warmUp)
                {
                    warmUp = false;
                    j--;
                }

            }
        }

        private static void PrepareTestData(
            int n, 
            out List<int> list, 
            out Dictionary<int, object> dictionary, 
            out List<int> sortedList, 
            out IQueryable<int> queryable)
        {
            list = new List<int>();

            var rand = new Random(42);

            for (int i = 0; i < n; i++)
            {
                int x;
                do
                {
                    x = rand.Next(int.MaxValue);
                } while (list.Contains(x));

                list.Add(x);
            }

            queryable = list.AsQueryable();

            dictionary = new Dictionary<int, object>();

            foreach (var item in list)
            {
                dictionary.Add(item, null);
            }


            sortedList = new List<int>();
            sortedList.AddRange(list);

            sortedList.Sort();
        }
    }
}

18 июля 2008