Wednesday, May 22, 2013

Unsupported major.minor version 51.0

Today I faced with the following exception:

java.lang.UnsupportedClassVersionError: com/rdiachenko/blackbox/alg/InsertionSortTest : Unsupported major.minor version 51.0
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClassCond(
at java.lang.ClassLoader.defineClass(
at Method)
at java.lang.ClassLoader.loadClass(
at sun.misc.Launcher$AppClassLoader.loadClass(
at java.lang.ClassLoader.loadClass(
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.loadClass(
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.loadClasses(
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(

Reason: Java sources were compiled with JDK 7, but were running on the lower JDK 6.
Solution: use higher (or the same) JDK during runtime and lower (or the same) during compile time.

Verstion 51.0 in exception message means J2SE 7. Here the list of all versions:

Wednesday, May 15, 2013

JavaScript plugin for Eclipse

Found a nice plugin for Eclipse which provides a pretty handy work with JavaScript - VJET.

VJET JavaScript IDE is an Eclipse plugin that provides a fully integrated development environment for JavaScript. Its main features:

- Code Assistance
- Code Search
- Syntax and Semantic Checking
- Type Declarations using VJETDoc
- Execution/Debugging

The project's site is here:
The update site is here:

Install and run Windows applications on Fedora/Ubuntu

PlayOnLinux is a tool which allows to install/run Windows applications under Linux. It is a kind of shell for wine.

Installation for Fedora:

$ wget
$ sudo cp  playonlinux.repo /etc/yum.repos.d/
$ sudo yum install playonlinux

Installation for Ubuntu here