how to run a class file created by user not created by copiler

Question

I opened the class file in notepad. copied the content of it and pasted in another notepad and saved it at with the same class name with the ".class" extention. then I tried to run that new class file and got the errors as.

Exception in thread "main" java.lang.UnsupportedClassVersionError: print : Unsupported major.minor version 8242.8224
        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.access$000(Unknown Source)
        at java.net.URLClassLoader$1.run(Unknown Source)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.loadClassInternal(Unknown Source)

Normally when you get that error (when you're not trying to run a .class file copied in notepad) it's because the version of Java you're trying to run it with is older than (and thus does not support) the version used to compile. This is not the case with your error. — Reinstate Monica -- notmaynard, Dec 30 '13 at 19:01
I just wanted to experiment different things and nothing else.. — Ashish Khatri, Jan 03 '14 at 09:05
I downloaded the JDK6 form the oracle website and installed it. — Ashish Khatri, Jan 03 '14 at 09:07

Mike Thomsen · Answer 1 · 2013-12-30T19:13:35.440

Class files are binary files, so you probably copied a corrupted view of it. You don't want to mess with Java class files by hand, unless you are willing to learn the JVM's bytecode.

If you REALLY want to do this, I suggest getting a hex editor that lets you copy and paste.

EDIT

One other thing, there's no value in messing with Java bytecode unless you are writing a compiler or something like Hibernate that really gets dirty with a class file at runtime. Meaning there is literally no normal business case for manipulating bytecode and you are almost invariably going to introduce a series of "WTF WERE YOU THINKING?!" level errors into a library or application if you don't do it right and with a good reason. One particular reason is that Java and JVM bytecode have a relationship much like C/C++ and Assembly. Sure you can disassessmble a C/C++ app and throw in some hand-coded assembly. However chances are you will introduce undebuggable errors into the app (those errors will be related to your hand-jamming bytecode/assembly into the app, not the code from your codebase that you wrote in the high level language).

Yep. The other answers are (in this case) wrong; there's never been a Java version 8242.8224. — Reinstate Monica -- notmaynard, Dec 30 '13 at 18:58

score -1 · Answer 2 · edited May 23 '17 at 10:25

-1

This means your javac version is different from your java version. see

How to fix java.lang.UnsupportedClassVersionError: Unsupported major.minor version

edited May 23 '17 at 10:25

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answered Dec 30 '13 at 18:53

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how to run a class file created by user not created by copiler

2 Answers2