JDK Wrong Version

Question

Everyone!

I have a java program with jar libraries that works on the following JDK version:

java -version
java version "1.8.0_102"
Java(TM) SE Runtime Environment (build 1.8.0_102-b14)
Java HotSpot(TM) 64-Bit Server VM (build 25.102-b14, mixed mode)

I need to make it compile on a supercomputer that works on the following JDK version:

java -version
java version "1.8.0_66"
Java(TM) SE Runtime Environment (build 1.8.0_66-b17)
Java HotSpot(TM) 64-Bit Server VM (build 25.66-b17, mixed mode)

As you can see they all have the same JDK which is JDK 8. However, when compiling using:

javac myFile.java 

The following error appears:

class file has wrong version 51.0, should be 48.0

It seems that the compiling is done on another JDK (other than 8). Can anyone please help me solve this problem?

Kindest Regards!

• Jon Skeet: And what happens when you run javac --version? When you run java --version you're only showing the version of the JRE, not the JDK...
• Gokul Raj Kumar: Similar question stackoverflow.com/questions/3535722/…
• ZAM.: I tried javac -version and the following appears javac: invalid flag: -version
• Stefan Hegny: javac **--**version
• ZAM.: I tried both and none of them works, do anyone have an idea why it doesn't work? putting in mind that when using java -version it works fine.

Answer 1

java.lang.UnsupportedClassVersionError happens because of a higher JDK during compile time and lower JDK during runtime.

J2SE 8=52,
J2SE 7=51,
J2SE 6.0=50,
J2SE 5.0=49,
JDK 1.4=48,
JDK 1.3=47,
JDK 1.2=46,
JDK 1.1=45

First Rule: Java version must be same on your local pc and server. Otherwise this kind of unwanted problem may arise.

For more checking, You can check

java --version

javac --version

It will make clarify of jdk and jre version mismatch. If it shows various version, then uninstall other versions and build your project and deploy on server.

Another answer is similar to your problem is here: Cannot compile Java code - "class file has wrong version 52.0, should be 48.0"

Resource Link:

Exception in thread "main" java.lang.UnsupportedClassVersionError: com/crunchify/Main : Unsupported major.minor version 51.0