An upgrade to berth 9.3.1.v20150714 caused an unsupported major .minor version 52.0

Question

The error message does not seem useful to you. Any idea what is going wrong?

Exception in thread "main" java.lang.UnsupportedClassVersionError: org/eclipse/jetty/server/Handler : Unsupported major.minor version 52.0 at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClass(ClassLoader.java:800) 

Answer 1

This is a standard Java bug indicating that you are using an older JVM than the classes you are trying to run. (the numbers of the Unsupported major.minor version may vary depending on the scenario, but the number you provided indicates the version of Java you need).

I usually use the Wikipedia article “Java Class File” to find out which version number of the major.minor file translates as far as possible as a Java JVM requirement.

As for Jetty 9.3+, which requires Java 8 per announcement message.

Answer 2

This error usually means that the JRE installed on your computer is older than the minimum value required by the project / library.

I suspect Jetty 9.3.1 now requires at least JRE 1.7

What returns "java -version" in the console?