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  1. JDK
  2. JDK-6196068

Class.forName throws NoClassDefFoundError on miscapitalized classname

    Details

    • Type: Bug
    • Status: Closed
    • Priority: P4
    • Resolution: Duplicate
    • Affects Version/s: 5.0
    • Fix Version/s: None
    • Component/s: core-libs
    • Labels:

      Description

      FULL PRODUCT VERSION :
      java version "1.5.0-beta"
      Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0-beta-b32c)
      Java HotSpot(TM) Client VM (build 1.5.0-beta-b32c, mixed mode)

      Also found in:
      java version "1.4.2_05"
      Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.2_05-b04)
      Java HotSpot(TM) Client VM (build 1.4.2_05-b04, mixed mode)

      ADDITIONAL OS VERSION INFORMATION :
      Microsoft Windows 2000 [Version 5.00.2195]

      A DESCRIPTION OF THE PROBLEM :
      Class.forName(String) throws a NoClassDefFoundError when given an incorrectly-capitalized class name and when the class file is loaded from a case-insensitive filesystem. Class.forName(String) should always throw a ClassNotFoundException in this case.

      I suspect the problem occurs when a class file is found (usually because the filesystem is case-insensitive) but does not contain the expected class (because class names are case-sensitive).

      The internal filesystems of Jar files are case-sensitive, so jar-based class loaders will not be subject to this bug -- and indeed, Class.forName("java.lang.class") correctly raises ClassNotFoundException (since java.lang.Class is stored in rt.jar, it won't come up as a match).

      STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
      Compile and run the test code on a Windows machine (but not within a jar file).

      EXPECTED VERSUS ACTUAL BEHAVIOR :
      EXPECTED -
      Class.forName(String) should raise a ClassNotFoundException, since the class name does not correspond to an actual class.
      ACTUAL -
      Class.forName(String) raised a NoClassDefFoundError after it found a class file (in the current directory), but that file didn't contain a class with the given name.

      ERROR MESSAGES/STACK TRACES THAT OCCUR :
      java.lang.NoClassDefFoundError: classload (wrong name: ClassLoad)

      REPRODUCIBILITY :
      This bug can be reproduced always.

      ---------- BEGIN SOURCE ----------
      public class ClassLoad {
        public static void main( String[] argv ) {
          try {
            Class.forName( "classload" );
          }
          catch (Throwable t) {
            System.err.println( t );
          }
        }
      }
      ---------- END SOURCE ----------

      CUSTOMER SUBMITTED WORKAROUND :
      Pretend NoClassDefFoundError is equivalent to ClassNotFoundException.
      ###@###.### 2004-11-16 18:37:11 GMT

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              • Assignee:
                darcy Joe Darcy
                Reporter:
                gmanwanisunw Girish Manwani (Inactive)
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                  Updated:
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