Error due to version compatibility in running jar file

Question

I have created a jar file using JDK 8.0 and I tried to run the jar file in a system which is having JRE 7.0, but I am getting an error like this:

C:\Users\admin\Desktop>java -jar test.jar 
Exception in thread "main" java.lang.UnsupportedClassVersionError: test : Uns
upported major.minor version 52.0
 at java.lang.ClassLoader.defineClass1(Native Method)
 at java.lang.ClassLoader.defineClass(Unknown Source)
 at java.security.SecureClassLoader.defineClass(Unknown Source)
 at java.net.URLClassLoader.defineClass(Unknown Source)
 at java.net.URLClassLoader.access100ドル(Unknown Source)
 at java.net.URLClassLoader1ドル.run(Unknown Source)
 at java.net.URLClassLoader1ドル.run(Unknown Source)
 at java.security.AccessController.doPrivileged(Native Method)
 at java.net.URLClassLoader.findClass(Unknown Source)
 at java.lang.ClassLoader.loadClass(Unknown Source)
 at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
 at java.lang.ClassLoader.loadClass(Unknown Source)
 at sun.launcher.LauncherHelper.checkAndLoadMain(Unknown Source)

What change am I need to make in my jar file creation. So that it will run without version compatibility?

• OO7: If you created project in Eclipse then try changing project facet Java to 1.7 & compiler version to 1.7. Then try to run jar with system having JDK 1.7.
• androidGenX: @OO7 I am using CMD and notepad, no IDEs
• OO7: What is target system OS ?
• androidGenX: Target may be start from java 7.0 and can be java 8.0 also
• Kishan Bheemajiyani: @androidGenX r u running on the JDK 8? and what is your class path set?

Answer 1

You need to use the -source option for javac. For example:

javac -source 1.7 foo/Bar.java

In theory you can specify the source and target options separately, but judging by your comment, it sounds like you can't use Java 8 language features at all when targeting 1.7.

Note that this only covers your own source code. If xbasej-20091203.jar was built against Java 8, you'll need to find a version which targets Java 7 instead.

• androidGenX: I tried but I am getting error in compilation like 'javac: target version 1.7 conflicts with default source release 1.8'
• Jon Skeet: @androidGenX: Right - sounds like you can't use the Java 8 language features at all when targeting 1.7 then.
• androidGenX: Can you tell how buddy? I tried like this : C:\TIPL\GCST>javac -target 1.7 -classpath lib/xbasej-20091203.jar Example2.java javac: target release 1.7 conflicts with default source release 1.8
• Jon Skeet: @androidGenX: Right, it sounds like you can't use Java 8 language features when targeting 1.7, so just use -source 1.7. I've updated my answer.
• androidGenX: 1.8?? can you write here??