I am trying to replace standard JVM of jdk1.8.0_112 with Dynamic Code Evolution VM using
DCEVM-light-8u112-installer.jar
but when i checked jvm version after patching with command
c:>java -version
it is still showing same Server VM as below
1 java version "1.8.0_112"
2 Java(TM) SE Runtime Environment (build 1.8.0_112-b15)
3 Java HotSpot(TM) 64-Bit Server VM (build 25.112-b15, mixed mode)
at line number 3, i am expecting type of Server VM as
Dynamic Code Evolution 64-Bit Server VM (build 25.71-b01-dcevmlight-10, mixed mode)
please guide me on this
The light version of the DCEVM project provides a single jvm.dll file that is a replacement for the default jvm.dll file included with Oracle/OpenJDK JDKs. The light version does not overwrite the file included with the JDK/JRE installation but rather installs the DCEVM JVM as an alternate implementation. Therefore, java -version will continue to show the default Java version details.
If DCEVM was installed successfully, java -version -XXaltjvm=dcevm will show the DCEVM version details, as expected.
java -version will return the DCEVM JVM version details if the full version of DCEVM is installed. Currently the DCEVM project provides full binaries only for Java 7. However, there is very little functional difference between the light and full versions so there is no real need to install the full version.
Related
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 installed the latest version of Java and when I try to run eclipse it says:
Version 1.6.0_65 of the JVM is not suitable for this product. Version: 1.8 or greater is required.
I searched many forums and found the java -version command. When I run from the terminal I get:
java version "1.6.0_65" Java(TM) SE Runtime Environment (build
1.6.0_65-b14-466.1-11M4716) Java HotSpot(TM) 64-Bit Server VM (build 20.65-b04-466.1, mixed mode)
But when I open Java on my system preferences it says I have 1.8.
Why? What do I do?
It says 1.6 because it is the pre-installed version in your system. But in order to install different version of Java, you need to install the latest development kit from Oracle's website i.e. http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html
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 downloaded Eclipse Luna and ran from the terminal in Mac OS X:
> /Applications/Eclipse.app/Contents/MacOS/eclipse
JavaVM: requested Java version (1.8.0) not available. Using Java at "/System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Home" instead.
However, I have:
> java -version
java version "1.8.0_20"
Java(TM) SE Runtime Environment (build 1.8.0_20-b26)
Java HotSpot(TM) 64-Bit Server VM (build 25.20-b23, mixed mode)
What am I doing wrong?
Luna seems currently having a bug: it installs the wrong Java version as its own dependency and then fails claiming that version is wrong.
You need to install Java separately (download official SDK from Oracle website) and make that one default. Be sure you install SDK and not the web plugin. Type java -version to verify the version and then which java to tell the exact path. Edit eclipse.ini as usual and set there the correct path to Java executable.
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.