error in struts program

i am doing a project in tsruts problem is that sometimes it gives error

Bad version number in .class file
	org.apache.jasper.servlet.JspServlet.service(JspServlet.java:244)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:802)

root cause

java.lang.UnsupportedClassVersionError: Bad version number in .class file
	java.lang.ClassLoader.defineClass1(Native Method)
	java.lang.ClassLoader.defineClass(ClassLoader.java:620)
	java.security.SecureClassLoader.defineClass(SecureClassLoader.java:124)
	java.net.URLClassLoader.defineClass(URLClassLoader.java:260)
	java.net.URLClassLoader.access$100(URLClassLoader.java:56)
	java.net.URLClassLoader$1.run(URLClassLoader.java:195)
	java.security.AccessController.doPrivileged(Native Method)
	java.net.URLClassLoader.findClass(URLClassLoader.java:188)
	org.apache.jasper.servlet.JasperLoader.loadClass(JasperLoader.java:156)
	org.apache.jasper.servlet.JasperLoader.loadClass(JasperLoader.java:69)
	org.apache.jasper.JspCompilationContext.load(JspCompilationContext.java:548)
	org.apache.jasper.servlet.JspServletWrapper.getServlet(JspServletWrapper.java:136)
	org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:307)
	org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:292)
	org.apache.jasper.servlet.JspServlet.service(JspServlet.java:236

please tell me what this error can be

Check the version of JDK that is trying to execute your code, It might be the unsupported version of the source code

@ deepak thanks for your reply

i am using java EE 5.0 during struts program &

jdk1.5.0_09

Aditi agarwal wrote:i am using java EE 5.0 during struts program &
jdk1.5.0_09

If you are using eclipse check the "Java Compiler Compliance level", check the version JDK libraries, Please make sure that JDK supports your source code, if any of the predefnied class files imported are not supported with JDK you use then you will get this error

I am using MyEclipse 8.5 please guide me for that

thnak you

I am not sure for MyEclipse but in Eclipse i do this way,Right click on the project, select Properties,then select Java Compiler from the list shown , check the version the compiler uses. Then Click java build path, check whether the required JDK library is added.

Please check whether all your predfined classes are supported by the current version you use.

@deepak thanks for your replie

i have checked the same way you have told in eclipse

my java compiler level is 1.4 &

in java build path all my J2EE 1.4 libraries are already added

now please tell me how to check that my all predefined classes are supported by current version that i use ?

thank you

Just change the compiler level to 1.5,Remove your j2ee 1.4 library and add JDK 1.5 , hope that might resolve the issue..

I am not sure whether a perfect tool exists to find out the JDK version of a class file but you can code for this

public static void main(String[] args) throws Exception {
        if (args.length != 1) {
            System.err.println("Usage: java version <.class file>");
            System.exit(1);
        }

if (! new File(args[0]).exists()) {
            System.err.println(args[0] + " does not exist!");
            System.exit(2);
        }

DataInputStream dis = new DataInputStream(
                                 new FileInputStream(args[0]));
        int magic = dis.readInt();
        if (magic != 0xcafebabe) {
            System.err.println(args[0] + " is not a .class file");
            System.exit(3);
        }

int minor = dis.readShort();
        int major = dis.readShort();
        System.out.println("class file version is " + major + "." + minor);

String version = null;
        
        if (major < 48) {
            version = "1.3.1";
        } else if (major == 48) {
            version = "1.4.2";
        } else if (major == 49) {
            version = "1.5";
        } else if (major == 50) {
            version = "6";
        } else {
            version = "7";
        }
        System.out.println("You need to use JDK " + version + " or above");   
    }

Hello,
I think this is related to something like class being compiled with the JDK that has higher version(say 1.6) than the one you are trying to run the class on(say 1.5).
Backward compatibility is always there so class compiled using 1.4 as in your case should run fine on the Java EE 5.

What version of Struts you are using? I am not sure if Struts 2 can work with JDK 1.4 as I havent worked with it yet.

Regards,
amit

@Aditi Any improvement?

nope deepak no improvement nothing can be done in this case tll now

Did you check the versions of your predefined classes? change java compiler level to 1.5 and add JDK 1.5 to build path, remove 1.4.

i have done every possible change which i can try