When I run $ javac Simulator.java then I get the following warning:
warning: ./particle_simulator/Atom.class: major version 51 is newer than 50, the highest major version supported by this compiler.
I don't know why I suddenly get this warning as I haven't made substantial changes to my code. Nevertheless, how do I upgrade my Java compiler?
I'm running Mac OSX 10.7.5 and my Java version is below:
java version "1.6.0_65"
Java(TM) SE Runtime Environment (build 1.6.0_65-b14-462-11M4609)
Java HotSpot(TM) 64-Bit Server VM (build 20.65-b04-462, mixed mode)
Download the JDK from Oracle: http://www.oracle.com/technetwork/java/javase/downloads/ . Make sure you get the OSX version. It has its own installer so installation should be pretty straight forward.
Related
I have just downloaded Eclipse and tried to run it, and it gave me this error message:
Error: opening registry key 'Software\JavaSoft\Java Runtime Environment
Error: could not find java.dll
Error: Could not find Java SE Runtime Environment.
After closing the errors, it sends me to this site:
https://download.eclipse.org/oomph/jre/?vm=1_1_8_0_64_0&pn=Eclipse%20Installer&pu=http://wiki.eclipse.org/Eclipse_Installer&pi=http://download.eclipse.org/oomph/jre/128x128.png
I have already reinstalled the jdk multiple times.
After following some other posts i saw, i have also made sure that %JAVA_HOME% was included in PATH
(%JAVA_HOME% = C:\Program Files\Java\jdk-13.0.1)
to java -version i got:
java version "1.8.0_231"
Java(TM) SE Runtime Environment (build 1.8.0_231-b11)
Java HotSpot(TM) 64-Bit Server VM (build 25.231-b11, mixed mode)
Thank you in advance for the help!
Edit:
I had both jdk-13.0.1 and jre 1.8.0 installed
After reinstalling only jdk 13.0.1 (and uninstalling jre 1.8.0), java -version gave me:
java version "13.0.1" 2019-10-15
Java(TM) SE Runtime Environment (build 13.0.1+9)
Java HotSpot(TM) 64-Bit Server VM (build 13.0.1+9, mixed mode, sharing)
I'm using Windows 10 Pro
EclipseIDE 2019-12 64bit
According to this answer maybe you messed up with your registry, make sure all java removed first and reinstall JRE.
For me if I want to develop java apps, I would install JDK instead of JRE, after install pls check java & javac command exist
'Software\JavaSoft\Java Runtime Environment
Error: could not find java.dll
Error: Could not find Java SE Runtime Environment. After closing the
errors, it sends me to this site:
https://download.eclipse.org/oomph/jre/?vm=1_1_8_0_64_0&pn=Eclipse%20Installer&pu=http://wiki.eclipse.org/Eclipse_Installer&pi=http://download.eclipse.org/oomph/jre/128x128.png
I have already reinstalled the JDK multiple times. After following some other posts I saw, I have also made sure that %JAVA_HOME% was included in PATH (%JAVA_HOME% = C:\Program Files\Java\jdk-13.0.1)
to java -version I got:
java version "1.8.0_231"
Java(TM) SE Runtime Environment (build 1.8.0_231-b11)
Java HotSpot(TM) 64-Bit Server VM (build 25.231-b11, mixed mode)
Thank you in advance for the help!
Edit:
I had both jdk-13.0.1 and jre 1.8.0 installed
After reinstalling only jdk 13.0.1 (and uninstalling jre 1.8.0), java -version gave me:
java version "13.0.1" 2019-10-15
Java(TM) SE Runtime Environment (build 13.0.1+9)
Java HotSpot(TM) 64-Bit Server VM (build 13.0.1+9, mixed mode, sharing)
I'm using Windows 10 Pro
EclipseIDE 2019-12 64bit
share edit
asked
1 hour ago
Csalagovits Máté
1●11 bronze badge edited
5 secs ago
One thing I noticed is the JAVA_HOME path refers to JDK 13, while the "java -version" command points to 1.8. Specify the version of Windows and Eclipse you have used in this question. Also, make sure you restart the PC after installing Java. – Shankar P S 52 mins ago
#ShankarPS Edited the question to adress your concerns – Csalagovits Máté 2 mins ago
I am trying to migrate a tomcat server.
Both are using tomcat7 version and all is supossed to be ready to take my java/jsp files from one server to another.
I did and I got UnsupportedClassVersionError error.
It was normal as in the old one I had JRE 1.8 version and in the new installation I had JRE 1.7 version (both from Oracle).
I proceeded to upgrade the second to 1.8. And everything was fine as in the new the output for java -version is:
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)
While in the old one:
java version "1.8.0_131" Java(TM) SE Runtime Environment (build
1.8.0_131-b11) Java HotSpot(TM) 64-Bit Server VM (build 25.131-b11, mixed mode)
In both echo $JAVA_HOME outputs:
/usr/lib/jvm/java-8-oracle
I restarted tomcat and server itself... but the UnsupportedClassVersionError persists.
I don't know if:
Somewhere I still point to the JRE 1.7 installation
Or 1.8.0_191 is considered another version than 1.8.0_131
Note: the compiler is the same as they have not been recompiled. Just take the compiled ones from old server (where there is no problem version) to the new one.
Has anyone a hint for me?
Thank you very much
As pointed in comments, sometimes JAVA_HOME is not checked and the decision on what jvm should be used is taken with another criteria (can't say which ones). So removing the old version of java forced the process to choose the desired one as it was unique.
Everyone!
I have a java program with jar libraries that works on the following JDK version:
java -version
java version "1.8.0_102"
Java(TM) SE Runtime Environment (build 1.8.0_102-b14)
Java HotSpot(TM) 64-Bit Server VM (build 25.102-b14, mixed mode)
I need to make it compile on a supercomputer that works on the following JDK version:
java -version
java version "1.8.0_66"
Java(TM) SE Runtime Environment (build 1.8.0_66-b17)
Java HotSpot(TM) 64-Bit Server VM (build 25.66-b17, mixed mode)
As you can see they all have the same JDK which is JDK 8. However, when compiling using:
javac myFile.java
The following error appears:
class file has wrong version 51.0, should be 48.0
It seems that the compiling is done on another JDK (other than 8). Can anyone please help me solve this problem?
Kindest Regards!
java.lang.UnsupportedClassVersionError happens because of a higher JDK during compile time and lower JDK during runtime.
J2SE 8=52,
J2SE 7=51,
J2SE 6.0=50,
J2SE 5.0=49,
JDK 1.4=48,
JDK 1.3=47,
JDK 1.2=46,
JDK 1.1=45
First Rule: Java version must be same on your local pc and server. Otherwise this kind of unwanted problem may arise.
For more checking, You can check
java --version
javac --version
It will make clarify of jdk and jre version mismatch. If it shows various version, then uninstall other versions and build your project and deploy on server.
Another answer is similar to your problem is here: Cannot compile Java code - "class file has wrong version 52.0, should be 48.0"
Resource Link:
Exception in thread “main” java.lang.UnsupportedClassVersionError: com/crunchify/Main : Unsupported major.minor version 51.0
I have a jre installed installed in my windows.
When I use the command
java -version
I get the output -
java version "1.7.0"
Java(TM) SE Runtime Environment (build 1.7.0-b147)
Java HotSpot(TM) Client VM (build 21.0-b17, mixed mode)
I can see only the major version 1.7.
How to know which version of JRE update it is ?
Calling java -version will give you the installed version, including the update number (here: 51):
java version "1.7.0_51"
Java(TM) SE Runtime Environment (build 1.7.0_51-b13)
Java HotSpot(TM) 64-Bit Server VM (build 24.51-b03, mixed mode)
It seems like you have the base version installed, so there is no update number:
java version "1.7.0"
Java(TM) SE Runtime Environment (build 1.7.0-b147)
Java HotSpot(TM) Client VM (build 21.0-b17, mixed mode)
I guess the build gives you the update you have.
You can try this as well-
java -fullversion
Version number translation: 1.6.0_34 is, in English, Java 6 Update 34
Looking at this page from the release note: http://www.oracle.com/technetwork/java/javase/jdk7-naming-418744.html
It seems you have the 1st java 7 version.
Oracle periodically makes updates available and, when an update occurs, the version string will also include the update version number. So, JDK 7 update 4, or JDK 7u4, will have the version string "1.7.0_4".
Normally the jre folder is named something like 1.VersionNumber.0_UpdateNumber
For 64 bit you can find this folder under C:\Program Files (x86)\Java
If your version Number just look like this: 1.VersionNumber.0, this means that you have the first release of given Java Version.
I'm using Oracle JDK 1.8.0.45 on Kubuntu Linux which I installed following these instructions. I had to do the manual install since the automatic one didn't work.
Even with the Oracle JDK I still can't use javafx without manually setting the classpath. What could cause javafx to not be on the default classpath as it should be in 1.8?
EDIT: Java -version in terminal gives:
java version "1.8.0_45"
Java(TM) SE Runtime Environment (build 1.8.0_45-b14)
Java HotSpot(TM) 64-Bit Server VM (build 25.45-b02, mixed mode)