Encourage the JVM to GC rather than grow the heap?

(Note that when I say "JVM", I really mean "Hotspot", and I'm running the latest Java 1.6 update.) Example situation: My JVM is running with -Xmx set to 1gb. Currently, the heap has 500mb...

JVM crash :- Problematic frame: # V [libjvm.so+0x546720]

Production server has gone down and the preliminary analysis find that it has encountered a JVM crash. The jboss server log and GC log seems to be ok. And the jvm error log mention the...

Why is this Hotspot JVM option not the default? -XX:+PrintConcurrentLocks

By default, with Hotspot, a CTRL-Break thread dump will not list what threads are holding java.lang.concurrent locks. And I understand that with these locks, Hotspot cannot have information about...

jconsole not able to connect even though java process is running

After running the process for say 6 to 8 hours , jconsole is not able to connect to the java process. I tried telnet on that port and its going fine. [email protected]:~/harvester$ telnet localhost...

What is the maximum number of HTTP redirections allowed by all major browsers?

I am designing a web site, spread across many servers, and there are pages where I need up to chain up to 4 redirections in a row. I tried a few browsers (firefox, chrome, IE) and it seems to...

sending pictures from Android to Matlab on PC

I want Matlab to perform as a server and Android Java app to perform as a client. Android should transfer a byte array of size 460K to Matlab. I cannot manage to get the entire array correctly on...

Use of uninitialized value $form_data{"BuildAcct"}

*** SECOND UPDATE FOR SUNDAY*** Now at this point I have found some added success at displaying the desired sub The new snippet of code which enabled me to actually invoke a specific sub as I...

Drawing multiple paths in android

I am drawing closed paths in android canvas using finger movement. Here is my code for that switch (event.getAction()) { case MotionEvent.ACTION_DOWN: ...

Unable to record an Android app using JMeter

I'm trying to record browser activities of my Android mobile in Jmeter as explained here. I'm done with all the above settings, but Jmeter is unable to record the traffic. Is it like, mobile and...

Code for mikrotik router hotspot auto login page

Guys can any one help me to make an auto login script for my local mikrotik router hotspot login page ?? I had tried in vbscript but it only post values in username and password fields,it was not...

com.sun.tools.attach.AttachNotSupportedException: Unable to open socket file: target process not responding or HotSpot VM not loaded

I get AttachNotSupportedException while running jmockit tests on linux (ubuntu 64bit). Java version is 1.7.0_51. This JDK is from Oracle. Tests are run using ant(that probably is not...

Determining whether a particular JDK Method typically has an intrinsic implementation

Short of the reading the OpenJDK source code (which I'm not averse to) is there a reasonably comprehensive (or 'official') list of intrinsic operations within the Hotspot JVM (say for Intel)? For...

Hotspot JVM - G1GC Heap resizing issue

I was recently testing a presentation app with a relatively high concurrent load. The application is a java application and is running on Hotspot JVM (1.8.0_111). I could get a maximum throughput...

java and httpclient java.lang.NoClassDefFoundError

I have problem. import java.io.File; import java.io.IOException; import java.io.UnsupportedEncodingException; import org.apache.http.client.ClientProtocolException; import...

Html page not loading css and js files when loaded from a jar file into a JavaFx Webview

I have been searching the forum for answers and similar posts, but none have helped me resolve my issue. I am working on a standalone project - no server involved. And am trying to load a html...

How to remove Elasticsearch from Ubuntu?

I think that I already removed elasticsearch from my computer, and still I have some doubts. When I type: $ service elasticsearch status I get: elasticsearch.service Loaded: not-found...

ZK Time and Attendance device with PHP

I am using [ZKlib][1] [1]: https://github.com/dnaextrim/php_zklib to connect to my ZK time and attendance machine. It is using UDP/SOAP to connect to device. Everything is working fine on...

How to connect Python program(on PC) to an Android App(on Mobile Phone)?

I have created a python program which can detect the number of cars in a parking area(small scale MVP model)from a camera feed.I now need to create an Android application that shows the 'count' of...

Android Studio - Android Emulator Wifi Connected with No Internet

I have wasted a whole day trying out different solutions floating around in SO and other place mentioned to enable wifi on the android emulator but to no avail. Can anybody help me figure out how...

Environment variables are not getting expanded in JAVA_TOOL_OPTIONS

I am trying to integrate a javaagent for application monitoring. I'm using docker and I've setup an OpenJDK base image which is inherited by other application images. Since javaagent requires a...

Why does this small Java program make MacOS restart?

Code is as follows Set<Thread> threads = new HashSet<>(); Runnable r = () -> { try { Thread.sleep(Long.MAX_VALUE); } catch (InterruptedException e) { e.printStackTrace(); ...

OpenJ9 tomcat won't start with high -Xmx heap option

I have a Spring app running in a Tomcat 9.0.6 on Linux 64. Because it needs a lot of memory, I would like to try the OpenJ9 JVM which is supposedly more efficient in that regard (current heap...

Is there a way to implement captive portal on windows hotspot?

I am looking for a way to implement a captive portal for the windows 10 - mobile hotspot. The idea is to redirect all devices that connect to the hotspot to a webpage. I was able to find this...

Port 25 is blocked trying to send CDO email from Excel VBA

I have a VBA script to send email from Excel. The script worked yesterday from my hotel; however, today from home on my home network, I get this error: "The transport failed to connect to the...

npm install fails with bad signature error on Windows

I am using nvm to manage my node versions. I have a project that users node 6.10.2. With something as simple as npm install -g gulp I get the following error: write EPROTO...

Java HotSpot(TM) 64-Bit Server VM warning: Sharing is only supported for boot loader classes because bootstrap classpath has been appended

The error message I got while trying to debug my code Java HotSpot(TM) 64-Bit Server VM warning: Sharing is only supported for boot loader classes because bootstrap classpath has been...

How do I enable/disable hotspot or tethering mode programmatically on Android?

I see many references on Android's website to local Only Hotspot However I need to manage the cellular hotspot programmatically from a background service as I can do manually from the pulldown...

Apache Livy 0.7.0 Failed to create Interactive session

While creating a new session using apache Livy 0.7.0 I am getting below error. I am also using zeppelin notebook(livy interpreter) to create the session. Using Scala version 2.12.10, Java...

Alternative of Math.random in javascript

I am using Math.random() function to get an integer from range of 0 to 'max' number. But According to sonarqube, it is "Security Hotspots" medium issue. private getRandomInt(max) { return...

flutter run on iPhone simulator stucks on 'Xcode build done'. (it runs well in android emulator)

Question Hello, I'm having difficulty while running my Flutter App on iPhone simulator. It stucks on 'Xcode build done'. BTW, It runs very well on Android emulator. It's my first time to ask a...