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Questions tagged [java]

Programming language and runtime environment that allows compiled Java programs to run unchanged on most hardware and software platforms

1
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2answers
2k views

Linux out of memory on VPS

On my VPS (CentOS) 4GB ram (2 + 2 dynamically assigned when needed) and i have tomcat running with following options JAVA_OPTS="-Xms256m -Xmx2048m -XX:MaxPermSize=256m". Now when i try to start ...
129
votes
3answers
146k views

How can I upgrade to Java 1.8 on an Amazon Linux Server?

I tried sudo yum update but it just keeps java "1.7.0_75". I need 1.8 for it to work with another application but can't figure out how to upgrade it. Do I need to manually install it somehow? There's ...
74
votes
5answers
138k views

Practical maximum open file descriptors (ulimit -n) for a high volume system

We recently began load testing our application and noticed that it ran out of file descriptors after about 24 hours. We are running RHEL 5 on a Dell 1955: CPU: 2 x Dual Core 2.66GHz 4MB 5150 / ...
4
votes
3answers
35k views

How do I fix a 'Failed to retrieve RMIServer stub' JMX error?

I just completed a migration from Windows server 2008 R2 to Ubuntu 10.04. I manage a java application (Java 6, Tomcat) that is having some performance issues. I'd like to use JMX to try and ...
0
votes
5answers
7k views

Configuring Apache, Tomcat, mod_jk and mod_rewrite to serve up tomcat from top-level

I'm trying to set up my java app as the main component of a new site. I have some static resources I'd like served by Apache, so I setup Apache and Mod_jk, with the following rules, JkMount /...
1
vote
2answers
261 views

Caveats when upgrading from Java 6 to Java 7 on hundreds of production servers [closed]

I am about to upgrade the JDK version from Java 1.6.0_37-b06 to Java 1.7.0_11.64 in a few hundreds of production servers, which run Tomcat servlets. The upgrade is a part of a large system upgrade ...
6
votes
1answer
1k views

Running some benchmarks using ab, and tomcat starts to really slow down

I'm running some benchmarks using apache bench for a java app that is running on tomcat. Say I run a test like: ab -c 10 -n 10000 http://localhost:8080/hello/world It will run just fine. If I ...
5
votes
5answers
27k views

How can I monitor memory usage for a windows-based JVM and trigger an alert if it gets too high?

I have an app that runs as a JVM in Windows 2008. I'd like to monitor it's memory usage and be sent an email if/when memory usage reaches a specific threshold. Is there a free utility or method for ...
5
votes
1answer
2k views

“runas” or “sudo” equivalent on AS400 IBM iSeries

I'm trying to invoke a program to run as another user (by getting input user/pwd) in AS400 OS using Java. Like runas in Windows or sudo in Unix — what can we do in AS400 OS? I am able to invoke basic ...
4
votes
2answers
5k views

Anyone know of any Free Java hosting services?

I have a java server I want to host on the net. I found google app engine, but it requires a lot of changes to the app. Basically, I want to put my compiled jar somewhere, then run and control it ...
1
vote
0answers
6k views

java.security.KeyStoreException: TrustedCertEntry not supported

I am trying to secure my private docker registry using SSL encryption. According to this, I need to copy a .crt and .key to a /certs directory and it will work. What I have now is a .csr, .keystore ...
1
vote
2answers
4k views

Weblogic administration console way too slow

I've installed weblogic 10.3.3, configured simple domain with default configuration. And after starting weblogic I cannot use it via admin console because it is starting too slow (~10 mins). It seems ...
75
votes
9answers
194k views

Can't seem to disable Java Automatic Update

I'm just tweaking out my new Windows 7 laptop and wanted to disable the automatic Java updating (and thus kill the silly jusched.exe background process), but I can't seem to get it to actually turn it ...
29
votes
3answers
36k views

Cannot install openjdk-8-jre-headless on Debian Jessie

This Friday I saw that I had 2 held back packages for some reason when I ran apt-get upgrade, so naturally I did what any inexperienced sysadmin would do and uninstalled the packages in the hopes that ...
8
votes
5answers
7k views

Suggestions for free/cheap asset/patch management software (Adobe, Java, etc)

I am using WSUS for Microsoft patching but would like something that will inventory and patch Adobe, Java, Firefox, Quicktime, etc. I have used Lumension in the past and it was OK but it is too ...
15
votes
5answers
14k views

I'm designing a system to handle 10000 TCP connections per second, what problems will I run into?

I have a relatively new 8-core box running CentOS. I would like to develop a stats server that uses TCP. It's very simple, it accepts a TCP connection, increments a counter and closes the connection. ...
10
votes
1answer
18k views

How can I restrict the java plugin to run only on certain sites in Internet Explorer?

I want to secure our centrally managed computers better and it is very difficult to automatically deploy the java runtime, but how to do that is another question. I find the security of Java ...
8
votes
3answers
31k views

How to generate new, 2048-bit Diffie-Hellman parameters with Java keytool?

We are non-experts trying - unsuccessfully so far - to update our web server (JBoss-5.1.0.GA) settings to meet Diffie-Hellman standards. After running a test on https://weakdh.org/sysadmin.html, we ...
7
votes
4answers
19k views

How can I install WildFly 8.0.0.Final as service on Ubuntu Linux?

I am trying to install the WildFly 8.0.0.Final application server on a Virtual Machine running Ubuntu 12.04 LTS. I've done some searches on Google, but I found only third-party scripts and, I think, ...
9
votes
5answers
14k views

How to reliably take Java Heap Dumps?

My team is running into difficulties when trying to take good heap dumps triggered by OutOfMemoryErrors. For specific reasons we are currently taking the dumps with jmap called from a bash script ...
5
votes
3answers
63k views

Setting Java Runtime setting for all users on a client PC

We have a problem with a java application running out of memory. Our (Windows XP) client PCs have JRE 1.6 version 18 installed. I want to increase the -Xmx runtime parameter for the JRE to 512M but I ...
4
votes
3answers
3k views

Java VM problem in OpenVZ

I bought a vps for hosting my java needs. But I can't run java on it. Everything about java is correctly installed but when I try to run java ("java -version" forexample) I get this error : Error ...
3
votes
5answers
20k views

Installing Tomcat on CentOS 5

Disclaimer: I am not a server admin, I am a windows user that has lead a life of sinful installation wizards and drag and drop I'm attempting to install Tomcat on CentOS 5 hosted by a MediaTemple ...
3
votes
3answers
2k views

Linux: which process consumed all the memory?

We have 4GB on our linux server but we can currently use only ~1.8GB for our java-server, which is the first java process listed below. (200 MB are free so we can maximal use 1.6GB + 0.2GB) The ...
2
votes
4answers
3k views

High load without explanation

I have a very high load on my machine and don't know what is responsible or how to find out. On the machine runs a jboss appserver and mysql. Here is a top from the user at peak time: top - 16:23:01 ...
12
votes
6answers
16k views

Open source tomcat log viewer

I'm managing several tomcat instances (aprox 30-35) and looking for some console to centralize the logs. I tried php-syslog-ng before (no with tomcat), and found it useful. I would like that these ...
12
votes
2answers
15k views

Disabling SSLv3 but still supporting SSLv2Hello in Apache

Many SSL clients, notably JDK 6, use the SSLv2Hello protocol to handshake with the server. Using this protocol does not mean you are using SSL 2.0 or 3.0 for that matter; it is merely a handshake to ...
9
votes
4answers
17k views

Constantly Increasing swap size in Linux and Swap space not being reclaimed?

I have a 8GB RAM linux box on which 4 tomcat servers are running. One of the them is set to 3000MB memory(jvm -Xms and -Xmx setting) and others are set to 1500MB. The swap partition is also set to ...
8
votes
3answers
6k views

How can I install a headless JDK on an Ubuntu Jaunty server?

I recently set up a build server that requires a JDK to run (for example, to compile the Java sources). The OpenJDK package in Ubuntu pulls in the OpenJDK JRE as a dependency which, in turn, depends ...
1
vote
4answers
4k views

java max heap size, how much is too much

I'm having issues with a JRuby (rails) app running in tomcat. Occasionally page requests can take up to a minute to return (even though the rails logs processed the request in seconds so it's ...
1
vote
2answers
1k views

Performance issue with JVM (1.6.0_22) invoking OS command on Solaris 10

My high-level problem is my build tool (Maven) which became suddenly very slow on a Solaris 10 environment. A build which was taking 8 minutes now takes 50 minutes. I narrowed this problem down to a ...
7
votes
1answer
4k views

Tomcat Excessive Memory Consumption

I have a fresh server running Ubuntu 11.04 (Natty) (64-bit). I started off by installing openjdk and tomcat6. When the Tomcat server starts up, it immediately uses 480+ MB of memory. This seems way ...
5
votes
1answer
1k views

Automatic updating of newer JRE on GNU/Linux

How can a GNU/Linux machine be set up to automatically update a newer version of the Java Runtime Environment (JRE)? The difficulty is wanting to use a newer version of Java (Java 7, at present) and ...
5
votes
3answers
6k views

How to run IPMI consoles now that NPAPI plugins are no longer supported?

I have a Tyan S5533 motherboard which serves as my NAS drive. It has a dedicated IPMI NIC, but I cannot start up the Java console since Firefox 52, Chrome/Chromium no longer support NPAPI plugins. I ...
4
votes
1answer
4k views

Linux Huge Pages Usage Accounting

I have configured Huge Pages for use with Java and it appears to be working well although I have a question about the accounting in /proc/meminfo. To illustrate # grep HugePages /proc/meminfo ...
4
votes
2answers
3k views

Performance problems when running Java desktop applications on Citrix Metaframe

We have a desktop Java application running within a Citrix Metaframe server farm and the performance, specially while starting up the app, is very unreliable. Sometimes it takes 15 seconds and ...
3
votes
2answers
1k views

Free java hosting? [duplicate]

Possible Duplicate: Anyone know of any Free Java hosting services? Could anyone tell me some free hosting on which I can run my java web application even for a day? I don't want free forever. ...
3
votes
1answer
778 views

Tomcat session replication issue

TL;DR - The node name in the sessionId is not being updated to the current node name in the backup when the primary goes down. Tomcat version - apache-tomcat-7.0.50 I have two nodes (2 instances of ...
3
votes
1answer
5k views

Tomcat 7.0.22 Windows service breaks with JRE update

If JRE update is run without first manually stopping the Tomcat service, Tomcat will no longer start after the next time it is stopped. This most often happens after rebooting per the JRE installer's ...
2
votes
2answers
9k views

IIS 7 + Tomcat 7 - how to reach http://localhost:8080/my_app under e.g. http://my_app.local

In brief: IIS 7 + Apache Tomcat 7 + isapi_redirect.dll: I have a deployed and working Tomcat-application available under http://localhost:8080/my_app. I would like to see the same content under http:...
1
vote
1answer
7k views

add-apt-repository: command not found in Ubuntu 10.04

I installed my VPS with Ubuntu 10.04 64 bit and I even checked with cat /etc/lsb-release and I got DISTRIB_ID=Ubuntu DISTRIB_RELEASE=10.04 DISTRIB_CODENAME=lucid DISTRIB_DESCRIPTION="Ubuntu 10.04....
1
vote
1answer
1k views

CentOS, Tomcat 6 failed and won't start - java issue?

Linux isn't my strong suit so bear with me if this seems a little newbish. I have a virtual linux box rented, has CentOS (not sure which version) and Apache with Tomcat 6. Over the past 24 hours, the ...
10
votes
7answers
23k views

How to block access to a file from being served by Tomcat?

We have a few tomcat servers and we just discovered that some files that we don't want public to have access to those files. To exemplify: Let say we have a folder /var/www/html/ that we are ...
4
votes
3answers
6k views

How to install Java JRE on FreeBSD with as few dependencies as possible

I've been trying to get Java working on my FreeBSD 7.1 server. I just want the runtime, since the JDK drags all kinds of unnecessary dependencies with it, and I just need it to run a jar file ...
3
votes
2answers
5k views

Access keystore on Sun ONE Webserver 6.1 for 2048 bit key length SSL

We want to get 2048 bit key length CSR requests. The browser based GUI provides us with a 1024 bit CSR and I don't know how to change that. It seems that 1024 bit key lengths will no longer ...
3
votes
1answer
782 views

installing java on freeBSD

I have a FreeBSD server with root access and I'm trying to install java on it. I've tried to install diablo from the /usr/ports/java/diablo-jre15 directory, and it gave me a URL to download a file to /...
2
votes
1answer
79 views

Which Hyperviser Solution for Java Applications?

Do you have any comment which of the available hypervisor solutions is best suited for Java applications? i.e. provides higher performance along with Java virtual machine? Our machines are mid-level ...
2
votes
2answers
2k views

Tomcat crashing after a few hours

I'm running a CentOS 6.5 64 bit OS with Tomcat and one web application. I use Apache (httpd) as a reverse proxy (ProxyPass) to the application. Until recently, it (Tomcat) has been running fine ...
1
vote
1answer
214 views

How to create a headless JDK on Ubuntu

I want to have a headless JDK on Ubuntu 14.04. As discussed in the question “How can I install a headless JDK on an Ubuntu Jaunty server?”, one option is to create my own jdk-headless package. I have ...
1
vote
1answer
487 views

glassfish v3 and java EE in production mode: what are the options to update a live web app?

I am building a web app using java EE and glassfish v3. I want to move it to production mode soon, however i have zero experience with using glassfish in production, i would appreciate if you give me ...