# Jan 4, 2018

solution:

`java.lang.UnsupportedClassVersionError`

**happens because of a higher JDK during compile time and lower JDK during runtime.**\
The version number shown describes the version of the JRE the class file is compatible with.

The reported major numbers are:

```
Java SE 9 = 53,
Java SE 8 = 52,
Java SE 7 = 51,
Java SE 6.0 = 50,
Java SE 5.0 = 49,
JDK 1.4 = 48,
JDK 1.3 = 47,
JDK 1.2 = 46,
JDK 1.1 = 45
```

To fix the actual problem you should try to either run the Java code with a newer version of Java JRE or specify the target parameter to the Java compiler to instruct the compiler to create code compatible with earlier Java versions.