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  1. JDK
  2. JDK-4625822

URLClassPath ignores jar if its Class-Path contains invalid URL

    Details

    • Type: Bug
    • Status: Closed
    • Priority: P4
    • Resolution: Won't Fix
    • Affects Version/s: 1.4.0
    • Fix Version/s: None
    • Component/s: core-libs
    • Labels:

      Description

      sun.misc.URLClassPath is currently implemented such that if a jar file declares
      a Class-Path manifest attribute, and the Class-Path attribute contains a
      malformed URL, then the MalformedURLException triggered by the URL will cause
      URLClassPath to ignore the jar file when loading resources. This seems
      inconsistent with the overall behavior of URLClassPath with respect to
      IOExceptions encountered while accessing URLs--i.e., tolerating the exception
      and continuing on to search subsequent URLs. It's also particularly
      inconsistent with the way new URLs encountered in jar indexes are handled: in
      the jar index case, a URL string which causes a MalformedURLException is simply
      ignored, but does not cause the enclosing jar file to be itself ignored.

      A simple test case demonstrates the problem:

        $ java -version
        java version "1.4.0-rc"
        Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.0-rc-b91)
        Java HotSpot(TM) Client VM (build 1.4.0-rc-b91, mixed mode)

        $ cat Foo.java
        public class Foo {
            public static void main(String[] args) {
                System.out.println("hello");
            }
        }

        $ javac Foo.java
        $ cat manifest1
        Manifest-Version: 1.0
        Main-Class: Foo

        $ jar cfm foo1.jar manifest1 Foo.class
        $ java -jar foo1.jar
        hello

        $ cat manifest2
        Manifest-Version: 1.0
        Main-Class: Foo
        Class-Path: invalid:url

        $ jar cfm foo2.jar manifest2 Foo.class
        $ java -jar foo2.jar
        Exception in thread "main" java.lang.NoClassDefFoundError: Foo

      The cause of the problem is in the code for URLClassPath.getLoader(int). In
      the section starting at line 220 of URLClassPath.java:

                  try {
                      loader = getLoader(url);
                      // If the loader defines a local class path then add the
                      // URLs to the list of URLs to be opened.
                      URL[] urls = loader.getClassPath();
                      if (urls != null) {
                          push(urls);
                      }
                  } catch (IOException e) {
                      // Silently ignore for now...
                      continue;
                  }

      In the scenario described above, the call to getLoader(url) succeeds, but the
      call to loader.getClassPath() (which attempts to construct URL objects from the
      jar file's Class-Path attribute string) throws a MalformedURLException, which
      transfers control to the catch block, which skips to the next iteration of the
      loop, effectively ignoring the successfully constructed loader. A simple fix
      would be to split the try block so that an exception thrown by
      loader.getClassPath() would not cause loader to be discarded.

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            • Assignee:
              Unassigned
              Reporter:
              mwarressunw Michael Warres (Inactive)
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