ClassLoader.defineClass throws NoClassDefFoundError on incorrect class name

Name: mgC56079 Date: 11/06/98


ClassLoader.defineClass(String name, byte[] b, int off, int len)
throws NoClassDefFoundError if name does not match the name derived from
the class data array.
According to javadoc, the call should result in a ClassFormatError:

    /**
     * Converts an array of bytes into an instance of class <code>Class</code>.
     * Before the Class can be used it must be resolved.
     * <p>
     * This method assigns a default <code>ProtectionDomain</code> to
     * the newly defined class. The <code>ProtectionDomain</code>
     * contains the set of permissions granted when
     * a call to <code>Policy.getPolicy().getPermissions()</code> is made with
     * a Codesource of <code>null,null</code>. The default domain is
     * created on the first invocation of <code>defineClass</code>, and
     * re-used on subsequent calls.
     * <p>
     * To assign a specific <code>ProtectionDomain</code> to the class,
     * use the <code>defineClass</code> method that takes a
     * <code>ProtectionDomain</code> as one of its arguments.
     *
     * @param name the expected name of the class, or <code>null</code>
     * if not known, using '.' and not '/' as the separator
     * and without a trailing ".class" suffix.
     * @param b the bytes that make up the class data. The bytes in
     * positions <code>off</code> through <code>off+len-1</code>
     * should have the format of a valid class file as defined
     * by the
     * <a href="http://java.sun.com/docs/books/vmspec/">Java
     * Virtual Machine Specification</a>.
     * @param off the start offset of the class data
     * @param len the length of the class data
     * @return the <code>Class</code> object that was created from the
     * specified class data
     * @exception ClassFormatError if the data did not contain a valid class
     * @exception IndexOutOfBoundsException if either <code>off</code> or
     * <code>len</code> is negative, or if
     * <code>off+len</code> is greater than <code>b.length</code>.
     * @see ClassLoader#loadClass(java.lang.String, boolean)
     * @see ClassLoader#resolveClass(java.lang.Class)
     * @see java.security.ProtectionDomain
     * @see java.security.Policy
     * @see java.security.CodeSource
     * @see java.security.SecureClassLoader
     * @since JDK1.1
     */
    protected final Class defineClass(String name, byte[] b, int off, int len)
throws ClassFormatError

==== here is the test demonstrating the bug (CLoader.java) ====
import java.io.FileInputStream;
public class CLoader {

    public static void main(String[] s) {
      MyClassLoader loader = new MyClassLoader();
      byte[] source=new byte[10000];
      int len;
      try {
          FileInputStream f=new FileInputStream("CLoader.class");
          len=f.read(source,0,source.length);
      }
      catch (Exception e) {
          e.printStackTrace();
          return;
      }
      try {
        loader.myDefineClass("incorrect.class.name",source,0,len);
        System.out.println("failed: unexpected success");
      }
      catch (ClassFormatError e) {
          System.out.println("passed");
      }
      catch (Throwable t) {
          System.out.println("failed");
          t.printStackTrace();
      }
    }

}

class MyClassLoader extends ClassLoader {

    public Class myDefineClass(String name, byte[] b, int off, int len) {
        return defineClass(name, b, off, len);
    }

}
==== sample run (jdk1.2fcsQ) ====
% java CLoader
failed
java.lang.NoClassDefFoundError: incorrect/class/name (wrong name: CLoader)
at java.lang.ClassLoader.defineClass0(Native Method)
at java.lang.ClassLoader.defineClass(Compiled Code)
at MyClassLoader.myDefineClass(Compiled Code)
at CLoader.main(Compiled Code)

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