I am using rjb to connect java classes in my rails application...
But I am getting this error can't create Java VM
My ruby -v gave me
ruby 1.9.3p484 (2013-11-22 revision 43786) [x86_64-linux]
and java --version
java version "1.7.0_79"
OpenJDK Runtime Environment (IcedTea 2.5.5) (7u79-2.5.5-0ubuntu0.14.04.2)
OpenJDK 64-Bit Server VM (build 24.79-b02, mixed mode)
I went through this post Error “can't create Java VM” trying to use Ruby Java Bridge (RJB) gem but the problem is I can not install 32 bit java as it is needed by some other application
I would download the jdk from oracle (http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html), the version you need. Then for your application set JAVA_HOME to that install directory. You can have multiple different jvms installed on a system.
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On of our (remote) developers needs to install FDT (an Eclipse based IDE) to compile some legacy ActionScript code. I've got FDT working on my Ubuntu 18.04 laptop just fine, but the dev is having trouble getting it to work on his Mac. When he has Java version 7, 8 or 9 installed he gets a message saying
we need legacy java you can download it here...
and if he uses Java version 6, it says it needs version 7 or more.
So I checked which version I have on my Ubuntu 18.04 laptop so he can get the same one, and to my surprise it says:
$ java -version
java version "1.8.0_191"
Java(TM) SE Runtime Environment (build 1.8.0_191-b12)
Java HotSpot(TM) 64-Bit Server VM (build 25.191-b12, mixed mode)
As far as I know Java is WAY ahead of version 1.8. So I logged into our production server (Ubuntu 16.04) and there we've got something similar:
$ java -version
openjdk version "1.8.0_191"
OpenJDK Runtime Environment (build 1.8.0_191-8u191-b12-0ubuntu0.16.04.1-b12)
OpenJDK 64-Bit Server VM (build 25.191-b12, mixed mode)
I checked out the OpenJDK website and there it says OpenJDK is now at version 11.
What version of Java my laptop is actually running so our dev can get the same version?
You are using Java 8.
The Mac problem is a historic one because the legacy question is for a 32-bit JVM for some programs and you need a 64-bit for Java 8.
Install the Java 6 the programs want and then install A newer java from oracle and he should be good to go.
Is PyCharm made using Java-Swing?
If it is, then how does it runs on a PC where JDK or JRE hasn't been set up yet?
When I look at my own PyCharm installation directory structure, I see a jre64 directory, which contains a Java installation.
And that seems to be a normal JRE:
$ ./pycharm-community-2018.2.4/jre64/bin/java -version
openjdk version "1.8.0_152-release"
OpenJDK Runtime Environment (build 1.8.0_152-release-1248-b8)
OpenJDK 64-Bit Server VM (build 25.152-b8, mixed mode)
So PyCharm comes with a Java distribution which it uses (even instead of an already available Java installation). Instead of my pre-installed and configured java 1.8.0_191, it uses the version it comes bundled with:
I created a new project using Clojure by doing this on a Mac:
lein new app clojure-noob
Created my uberjar using
lein uberjar
Sure enough, I can run this uberjar via:
java -jar target/uberjar/clojure-noob-0.1.0-SNAPSHOT-standalone.jar
And I get:
Hello, World!
Now I take this file to Windows 7 and give the same command:
java -jar clojure-noob-0.1.0-SNAPSHOT-standalone.jar
I seem to get an infinite wait. Why can’t I get to runt his .jar file on Windows?
The java version on Mac is:
java version "1.8.0_51"
Java(TM) SE Runtime Environment (build 1.8.0_51-b16)
Java HotSpot(TM) 64-Bit Server VM (build 25.51-b03, mixed mode)
The java version on Windows 7 is:
java version "1.8.0_66"
Java(TM) SE Runtime Environment (build 1.8.0_66-b18)
Java HotSpot(TM) Client VM (build 25.66-b18, mixed mode)
lein version gives the following: Leiningen 2.5.3 on Java 1.8.0_51 Java HotSpot(TM) 64-Bit Server VM
The answer is that I was trying to run the .jar from shared folders on a Windows 7 VM from VirtualBox running on a Mac. This IO is very slow.
When I just copy that file to, say, Desktop and run from there - the access is quiet fast. Thanks SubOptimal for helping me figure this out.
When I install myeclipse, it shows "needs java SE6 Environment",
How do I resolve this problem?
I have already installed jdk1.7 in my OS X Yosemite.
/Users/**** $ java -version
java version "1.7.0_75"
Java(TM) SE Runtime Environment (build 1.7.0_75-b13)
Java HotSpot(TM) 64-Bit Server VM (build 24.75-b04, mixed mode)
This is a problem with the online installer, which is a 32-bit application while Java 7 on OS X is 64-bit only.
You have two solutions : you can just download the offline installer, which should work fine, according to this support thread.
If this doesn't work, you'll have to install Java 6, which you can find here.
This was a problem with earlier installers. All current installers will not have this problem. Please download the latest release.
I'm running on ubuntu 12.04 and when I put in the terminal java -version I got this message:
java version "1.7.0_05"
Java(TM) SE Runtime Environment (build 1.7.0_05-b05)
Java HotSpot(TM) 64-Bit Server VM (build 23.1-b03, mixed mode)
but despite that, if I put in the terminal javadoc I receive a message as it isn't installed in my machine.
The Java Runtime Environment (JRE) doesn't include javadoc. It includes only the things required to run Java programs, not to develop them.
You need the JDK (Java Development Kit) which includes developer tools like javadoc, in addition to everything found in the JRE.
See the Ubuntu Java documentation.