thomasdarimont

Dump loaded classes from another JVM process with Java 9

We will use jrunscript and internal hotspot API to access and export the classfile data. To do that we will use 2 jrunscript processes, a "debuggee" process and a "debugger" jrunscript process. The debugger process will attach to and inspect the debuggee process (internal) via hotspot API. For this example we use the "latest" Java 9 build b41 on OSX.

Motivation for this example was given by the fact that the latest JDK 9 release b41 doesn't ship an rt.jar anymore. The content from rt.jar was now moved to a new platform specific format with the extension .jimage in the JDK_HOME/lib/modules.

You can find more information about the new packaging in Java 9 in Mark Reinholds blogpost: http://mreinhold.org/blog/jigsaw-modular-images

staltz

The introduction to Reactive Programming you've been missing

(by @andrestaltz)

---

This tutorial as a series of videos

If you prefer to watch video tutorials with live-coding, then check out this series I recorded with the same contents as in this article: Egghead.io - Introduction to Reactive Programming.

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dsyer

Aggressive Bean Instantiation and "Unproxyable" Beans

This project is a minimal setup depending only on spring-context but mimicking closely the mess that you get into with @EnableTransactionManagement (spring-tx) or @EnableGlobalMethodSecurity (spring-security). These annotations lead to registration of an InfrastructureAdvisorAutoProxyCreator which is responsible for locating the Advisor bean that provides the enabled feature. The mess is caused by aggressive bean instantiation in that component which can cause cascades of unsafe bean instantation

AlainODea

import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;

public class HelloCovariance {
  public static void main(String[] args) {
    ConcurrentHashMap<String, String> properties = new ConcurrentHashMap<>();
    Set<String> keySet = properties.keySet();
  }
}

wbroek

NOTE: Easier way is the X86 way, described on https://www.genymotion.com/help/desktop/faq/#google-play-services

Download the following ZIPs:
    
    ARM Translation Installer v1.1 (http://www.mirrorcreator.com/files/0ZIO8PME/Genymotion-ARM-Translation_v1.1.zip_links)
    
    Download the correct GApps for your Android version:
      Google Apps for Android 6.0 (https://www.androidfilehost.com/?fid=24052804347835438 - benzo-gapps-M-20151011-signed-chroma-r3.zip)
      Google Apps for Android 5.1 (https://www.androidfilehost.com/?fid=96042739161891406 - gapps-L-4-21-15.zip)
      Google Apps for Android 5.0 (https://www.androidfilehost.com/?fid=95784891001614559 - gapps-lp-20141109-signed.zip)

jasdeepkhalsa

// Long Polling (Recommened Technique - Creates An Open Connection To Server ∴ Fast)
(function poll(){
    $.ajax({ url: "server", success: function(data){
        //Update your dashboard gauge
        salesGauge.setValue(data.value);
    }, dataType: "json", complete: poll, timeout: 30000 });
})();

smougenot

  # stacktrace java as one message
  multiline {
    #type => "all" # no type means for all inputs
    pattern => "(^.+Exception: .+)|(^\s+at .+)|(^\s+... \d+ more)|(^\s*Caused by:.+)"
    what => "previous"
  }

deverton

{
    "template": "logstash-*",
    "settings" : {
        "number_of_shards" : 1,
        "number_of_replicas" : 0,
        "index" : {
            "query" : { "default_field" : "@message" },
            "store" : { "compress" : { "stored" : true, "tv": true } }
        }
    },

rednaxelafx

import java.io.*;
import java.util.*;
import sun.jvm.hotspot.memory.*;
import sun.jvm.hotspot.oops.*;
import sun.jvm.hotspot.debugger.*;
import sun.jvm.hotspot.runtime.*;
import sun.jvm.hotspot.tools.*;
import sun.jvm.hotspot.utilities.*;

public class DirectMemorySize extends Tool {

jehiah

#!/bin/sh

#
# a simple way to parse shell script arguments
# 
# please edit and use to your hearts content
# 


ENVIRONMENT="dev"