Playing with a little network program, created a Jar with netbeans. Runs just fine on my computer java 1.7.0.60, but when I take it to another computer that has a newer version of java 1.7.0_65 it will not run, I get this error:
C:\Program Files (x86)\Java\jre7\bin>java -jar ReverseEchoServer.jar
Exception in thread "main" java.lang.UnsupportedClassVersionError: reverseechose
rver/SocketClient : Unsupported major.minor version 52.0
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(Unknown Source)
at java.security.SecureClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.access$100(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.launcher.LauncherHelper.checkAndLoadMain(Unknown Source)
I have read several posts on here that talk about PATH, have looked at that but no luck. I belive its the version differance. Any advice would be most appreciated, Thanks!
Java class files compiled for Java 7 have Major/Minor versions 51/0. If you have a JVM implementation that wasn't prepared for Java 7, it would give you this error indicating "I don't know how to interpret and run this class file."
Try either compiling for an older JVM version, or upgrade your JVM.
Use the Target and specify the version in which it needs to be executed using target switch followed by version number.
javac -target 1.7 yourJarName.jar
Related
I have been trying to get VS Code to work and compile my Java code. I have finally given up trying to fix it myself.
I can't compile my code, I can't run it. I don't even know what's wrong with it. I really want to use VS Code because it's so clean and versatile (so please don't recommend me other IDEs).
Here is my code:
class DataStruct {
Run|Debug
public static void main(String[] args) {
System.out.println("Hello");
}
}
(Manually transcribed from this image.)
Here are my system variables:
This is what I get:
PS C:\Users\SvenH\AppData\Roaming\Code\User\java-ws> cd "c:\Users\SvenH\AppData\Roaming\Code\User\java-ws\" ; if ($?) { javac DataStruct.java } ; if ($?) { java DataStruct }
Error: A JNI error has occurred, please check your installation and try again
Exception in thread "main" java.lang.UnsupportedClassVersionError: DataStruct has been compiled by a more recent version of the Java Runtime (class file version 55.0), this version of the Java Runtime only recognizes class file versions up to 52.0
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(Unknown Source)
at java.security.SecureClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.access$100(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.launcher.LauncherHelper.checkAndLoadMain(Unknown Source)
PS C:\Users\SvenH\AppData\Roaming\Code\User\java-ws>
Make sure you are compiling and using the same java version.
One simple way to do it is:
uninstall JDK and JRE
download JDK and JRE, both at the same version
install them
This question already has answers here:
How to fix java.lang.UnsupportedClassVersionError: Unsupported major.minor version
(51 answers)
Closed 4 years ago.
I'm trying to help setup H2 database on their work computer. We successfully ran the installation, but every time we try to run it, we get the following error:
Exception in thread "main" java.lang.UnsupportedClassVersionError: org/h2/tool/Console : Unsupported major.minor version 51.0
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClassCond(Unknown Source)
at java.lang.ClassLoader.defineClass(Unknown Source)
at java.security.SecureClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.access$000(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
Could not find the main class: org.h2.tools.Console. Program will exit.
Java 1.6 is on the computer. The only thing I can think off that is causing this is that jdk was not installed yet, but I'm not sure if that will resolve the issue. Has anyone seen this error before?
The H2 classes you have have been compiled for Java 7 and above, so you need to upgrade your JVM to at least Java 7.
Since version 1.4.192 Java 7 is required (H2 build info)
It has previously been possible to compile the H2 drivers yourself for Java 6, not sure if tha source is still Java 6 compatible.
I am stuck on the following error. I don't know what type of error it is. What should I do?
C:\Users\shehzad\Desktop\Software>java -jar Untitled.jar
Exception in thread "main" java.lang.UnsupportedClassVersionError: FrontEnd/MainWindow : Unsupported major.minor version 52.0
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(Unknown Source)
at java.security.SecureClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.access$100(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Unknown Source)
at org.eclipse.jdt.internal.jarinjarloader.JarRsrcLoader.main(JarRsrcLoader.java:56)
Scenario is: I developed software that works fine in Ubuntu 14.04 Lts. It's JAR also works in Ubuntu, but when I tried this JAR
in Windows 7 it shows the above error.
Ubuntu Java version: 1.8.0_101
Windows Java version: 1.7.0_79
class version 52.0 means it requires Java 8 to run. You should for security reasons update your Windows Java anyway, so its time to go to Java 8. If you need Java 7 for something you can keep it as a private installation, but make sure the "javapath" as configured by the registry points to Java 8.
You can also start in a command window or via explorer link the right Java.exe without installing it as public version like this:
"c:\Program Files\java\jdk_1.8.0_102\bin\javaw.exe" -jar app.jar
Your jar file is compiled using 8u101 (major.minor version 52.0) and your trying to run on 7u79. Hence you end up in Unsupported major.minor version 52.0.upgrade your java to 8u101.
I have a class file that creates a monthly report by talking with a MySQL database, it also creates graphs as JPEGs (Hence why it must be in the TomCat Directory and not compiled as an app)
The front end simply uses this data to display a "Monthly Report".
My problem is I cannot figure out how to run the class file once it's compiled from the server. The Class file works 100% in eclipse and then automatically publishes to a server (locally).
I'm trying to compile the JAVA class file and run it locally on a Windows machine, the live version is on a Linux environment.
Here's what I have so far:
So compiling the class and running it: (Tried with -cp as well)
java C:\p_sys\tomcat\webapps\PR\WEB-INF\classes\au\gov\vic\pdd\PPA createreportsmonthly
We get the following error:
C:\p_sys\tomcat\webapps\PR\WEB-INF\classes\au\gov\vic\pdd\PPA\createreportsmonthly>java CreateMonthlyReportTable
Exception in thread "main" java.lang.NoClassDefFoundError: CreateMonthlyReportTa
ble (wrong name: au/gov/vic/ppd/PPA/createreportsmonthly/CreateMonthlyReportT
able)
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(Unknown Source)
at java.security.SecureClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.access$100(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.launcher.LauncherHelper.checkAndLoadMain(Unknown Source)
Can anyone help me out here?
* EDIT
Some clarity
CreateMonthlyReportTable.class is located within:
C:\p_sys\tomcat\webapps\PR\WEB-INF\classes\au\gov\vic\pdd\PPA\
have you tried
java -cp C:/p_sys/tomcat/webapps/PR/WEB-INF/classes<space> au.gov.vic.pdd.PPA.CreateMonthlyReportTable
should be a space character
Basically what I want to do is create a PDF from a iReport jrxml or jasper file.
The idea is to use this for reports over the net and the best solution I managed to find was to use a program like jasperstarter and then run the report with a connection to MSSQL database.
To get the connection going I had to download the latest net.sourceforge.jtds.jdbc.Driver.
The report works fine using iReport 5.1 but when I do follow the instructions from jasperstarter I get an "java.lang.UnsupportedClassVersionError" response.
jasperstarter command
jasperstarter pr -t generic -f pdf -i test_report.jasper -o test -u username -p password --db-driver net.sourceforge.jtds.jdbc.Driver --db-url jdbc:jtds:sqlserver://LOCAL-PC/Demo_DB
output
Exception in thread "main" java.lang.UnsupportedClassVersionError: net/sourcefor
ge/jtds/jdbc/Driver : Unsupported major.minor version 51.0
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClassCond(Unknown Source)
at java.lang.ClassLoader.defineClass(Unknown Source)
at java.security.SecureClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.access$000(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Unknown Source)
at de.cenote.jasperstarter.Db.getConnection(Db.java:69)
at de.cenote.jasperstarter.Report.fill(Report.java:220)
at de.cenote.jasperstarter.App.processReport(App.java:222)
at de.cenote.jasperstarter.App.main(App.java:107)
Please advice.
Basically, you are trying to run code that was compiled on / for Java 7 on an older JVM.
That doesn't work.
Either:
run your application on a Java 7 JVM (or later1); i.e. upgrade your Java version,
find a build of the JDTS driver that is suitable for your execution platform, or
find the source for the JDTS driver and build it for your platform.
For more detailed information on this exception and its causes, read:
http://stackoverflow.com/questions/10382929.
1 - Note that even Java 7 is end-of-life now. If you are still running that version of Java you should upgrade.
Make sure you have same JRE and JDK.
If not sure un-install download the latest JDK and try again.
Note that the JDK does install the JRE automatically.