Uploaded image for project: 'JDK'
  1. JDK
  2. JDK-6297388

JSR 199: compile against a class loader

    XMLWordPrintable

    Details

    • Subcomponent:
    • CPU:
      generic
    • OS:
      generic

      Description

      a problem JSP Containers face is to compile generated JSP Page Servlets
      against the classpath that makes up a web application. There is no way
      to find out the locations of the classes that make up the classpath.
      While it is possible for WEB-INF/classes and WEB-INF/lib, the JSP
      container needs intimate knowledge of the servlet container's class
      loading mechanism to add the rest (for example, the location of the
      servlet-api jar).

      This dependency on the servlet container has hindered the community to
      develop a portable, drop-in JSP container. While you can argue that JSP
      and Servlet containers are intimately coupled, any web framework that
      wants to compile code would face the same problem.

      An alternative, pioneered by the Cocoon community, and which I believe
      is being pursued by Jasper in Tomcat 5.5, is to use a compiler that
      resolves its classpath against a _classloader_ instead of a
      _filesystem_, using ClassLoader#getResource instead of java.io.File.
      Eclipse's Compiler has successfully been used to do this.

      While the JavaFileManager in principle looks like it could be adapted to
      a ClassLoader, it requires the "list" operation, an operation a
      ClassLoader cannot fulfill. Is listing all classes in a package
      necessary for this compiler to work? If so, a "Compile in current
      classloader", or more specific, "Compile in this webapp" will not be
      possible with JSR 199 which would be a shame. I remember that I once
      tried to make javac do this and I stumbled over this exact requirement
      before; eclipse's jdt did not need it.

      References:

      http://mail-archives.apache.org/mod_mbox/jakarta-tomcat-dev/200307.mbox/%###@###.###%3e

      http://jakarta.apache.org/tomcat/tomcat-5.5-doc/jasper-howto.html

      ###@###.### 2005-07-15 14:41:52 GMT

        Attachments

          Issue Links

            Activity

              People

              Assignee:
              sadayapalam Srikanth Adayapalam
              Reporter:
              ahe Peter Ahe
              Votes:
              0 Vote for this issue
              Watchers:
              6 Start watching this issue

                Dates

                Created:
                Updated:
                Resolved:
                Imported:
                Indexed: