I am getting this error when I include an opensource library that I had to compile from source. Now, all the suggestions on the web indicate that the code was compiled in one version and executed in another version (new on old). However, I only have one version of JRE on my system. If I run the commands:
$ javac -version
javac 1.5.0_18
$ java -version
java version "1.5.0_18"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_18-b02)
Java HotSpot(TM) Server VM (build 1.5.0_18-b02, mixed mode)
and check in Eclipse for the properties of the java library, I get 1.5.0_18
Therefore, I have to conclude something else, internal to a class itself, is throwing the exception?? Is that even possible?
The answer is
Deleting the project specific settings files (Eclipse workspace/project folder/.settings/) from the project folder also will do. Obviously, we need to do a project clean and build after deleting.
Have you tried doing a full "clean" and then rebuild in Eclipse (Project->Clean...)?
Are you able to compile and run with "javac" and "java" straight from the command line? Does that work properly?
If you right click on your project, go to "Properties" and then go to "Java Build Path", are there any suspicious entries under any of the tabs? This is essentially your CLASSPATH.
In the Eclipse preferences, you may also want to double check the "Installed JREs" section in the "Java" section and make sure it matches what you think it should.
You definitely have either a stale .class file laying around somewhere or you're getting a compile-time/run-time mismatch in the versions of Java you're using.
Always check for the obvious too. I got this error once when I accidently grabbed the wrong resource for the server's add and remove action. It can be easy to overlook.
I also got the same error. Reason for that I was compiling the project using Maven. I had JAVA_HOME pointing to JDK7 and hence java 1.7 was being used for compilation and when running the project I was using JDK1.5. Changing the below entry in .classpath file or change in the eclipse as in the screenshot resolved the issue.
classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/J2SE-1.5
or change in the run configuarions of eclipse as
changing the project to use java 1.7: For this to work follow those steps :
- Change Compiler Compliance Level
- Change your projects JRE/JDK to something of the same level(1.7 in my case)
- Do the same change in all the projects referenced by your project
- Change your run/debug configuration to use the JRE/JDK (or of the same level)
Not working?
- delete projects Bin directory
- Clean
- reBuild
Still not working?
in your project's directory: edit .settings/org.eclipse.jdt.core.prefs > make sure your target level is applied
Good Luck!
Another scenario where this could happen is when you are launching an instance of eclipse (for debug etc.) from a host eclipse - in which case, altering the project's level or JRE library on the project's classpath alone doesn't help. What matters is the JRE used to launch the target eclipse environment.
i solved this problem by changing jre required for server (in my case is tomcat). From Server tab in eclipse, double click on the server (in order to open page for server configuration), click on Runtime environment, then change JRE required
Did you compile with Eclipse? It uses a different compiler (not javac). That should not result in this error (if everything is configured properly), but you can try to compile it with javac instead.
If that fixed the problem, try to see if Eclipse has some incorrect compiler settings. Specifically have it target Java 5.
Also check any jar files in your project that have been compiled for a higher version of Java. If these are your own libraries, you can fix this by changing the target version attribute to javac
<javac destdir="${classes.dir}"
debug="on" classpathref="project.classpath" target="1.6">
Source: Stackoverflow.com