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  1. JDK
  2. JDK-4787534

jdk1.4.2 accepts invalid class files

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    • CPU:
      generic
    • OS:
      generic

      Description



      Name: viR10068 Date: 12/03/2002


      The javac compiler from JDK-1.3.1 generates incorrect values for the
      symbols from the range '\u0080' to '\u07ff' (for example, the symbol
      "\u04d0" is coded as 0xE09390 instead of 0xD390 as required by
      JVMS ed 2. Chapter 4.4.7).

      If:
        - java source file contains method name with the UNICODE symbols
          from the range '\u0080' to '\u07ff'
        - the file is compiled by the javac from jdk1.3.1
        - the class file version is changed from 45.3 (default value for jdk1.3.1)
          to 46.0
      then the JVM from jdk1.4.2 will not reject this invalid class file
      with the ClassFormatError (JVMS ed 2. Chapter 4.9.1).

      If there is intent to accept class files generated by javac 1.3.1 for
      compatibility reasons, then JVM should accept class files with the version
      ID 45.3 and not vice versa.

      To reproduce compile the example below by the javac1.3.1, change the
      class file version from 45.3 to 46.0 in any hex-editor and run the
      class file on the jdk1.4.2.
      --------------------------- test.java ------------------------------
      public class test {
          public static void main(String[] args){
              System.out.println(new test().a());
          }
          
          String a() {return "s";}

          String getStr00A\u04d0(){return "";}
      }
      --------------------------------------------------------------------
      % java -version
      java version "1.4.2-beta"
      Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.2-beta-b07)
      Java HotSpot(TM) Client VM (build 1.4.2-beta-b07, mixed mode)
      // if the version 46.0
      % /export/ld25/java/dest/jdk1.4.2/solaris-sparc/bin/java test
      s

      // if the version 45.3
      % java test
      Exception in thread "main" java.lang.ClassFormatError: test (Illegal UTF8 string in
      constant pool)
              at java.lang.ClassLoader.defineClass0(Native Method)
              at java.lang.ClassLoader.defineClass(ClassLoader.java:505)
              at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:123)
              at java.net.URLClassLoader.defineClass(URLClassLoader.java:250)
              at java.net.URLClassLoader.access$100(URLClassLoader.java:54)
              at java.net.URLClassLoader$1.run(URLClassLoader.java:193)
              at java.security.AccessController.doPrivileged(Native Method)
              at java.net.URLClassLoader.findClass(URLClassLoader.java:186)
              at java.lang.ClassLoader.loadClass(ClassLoader.java:299)
              at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:265)
              at java.lang.ClassLoader.loadClass(ClassLoader.java:255)
              at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:315)
      %

      ======================================================================

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              • Assignee:
                foliversunw Fred Oliver (Inactive)
                Reporter:
                vivsunw Viv Viv (Inactive)
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