The AntClassLoader created in one JUnitTask can not be used in another.

[Xu Xin <an...@gmail.com>]

Hello everyone,

I had a problem with JUnitTask, I have a couple of xml files where I also
have a lot of targets which contain <junit> tasks, originally I used the
Apache Ant's JUnitTask, but unfortunately the test run had performance
issue, that was caused by  each <test> has its own classloader, as a result
some static memory was created multiple times.

So I customized the JUnitTask by making the classloader created for each
test cacheable, the <junit> task has the same customer classpath elements
share the same classloader, so I can save the memory as I can, but the
strange thing is  junit testcase was not recognized, it seemed a
classloading issue, but after I ran the tests in DEBUG mode, I can find the
classloader hierarchy is correct, I do not know what's going wrong. The
snippet code is below:



private void createClassLoader() {
    Path userClasspath = getCommandline().getClasspath();

    if (userClasspath != null) {

    //get cached classloader from the pool if it exists
      classLoader = getCachedClassLoader(userClasspath);


      Path classpath = (Path) userClasspath.clone();
      if (includeAntRuntime) {
        log("Implicitly adding " + antRuntimeClasses + " to CLASSPATH",
            Project.MSG_VERBOSE);
        classpath.append(antRuntimeClasses);
      }
      if (reloading || classLoader == null) {

      //create a new one if no cached

        classLoader = getProject().createClassLoader(classpath);
        if (getClass().getClassLoader() != null
            && getClass().getClassLoader() != Project.class.getClassLoader())
{
          classLoader.setParent(getClass().getClassLoader());
        }
        classLoader.setParentFirst(false);
        classLoader.addJavaLibraries();
        // make sure the test will be accepted as a TestCase
        classLoader.addSystemPackageRoot("junit");
        // will cause trouble in JDK 1.1 if omitted
        classLoader.addSystemPackageRoot("org.apache.tools.ant");
        // testlogic: this fixes 'not a JUnitResultFormatter' issue
        classLoader.addSystemPackageRoot("org.testlogic.testrunner.ant.junit
");

        cacheClassLoader(userClasspath, classLoader);
      } else {

     //this is the cached one
        if (classLoader != null) {
          classLoader.setProject(this.getProject());
          classLoader.setClassPath(classpath);
            if (getClass().getClassLoader() != null
              && getClass().getClassLoader() != Project.class.getClassLoader())
{
            classLoader.setParent(getClass().getClassLoader());
          }

        }
      }

    }
  }

and next pass the classLoader to JUnitTestRunner as usual, the test class
can be loaded, as well as JUnit class: TestSuite and Test, but when
constructing TestCase, TestSuite complains the test class is not
implementation of Test, but I can see the test class was loaded by cached
AntClassLoader, and TestSuite and Test were loaded by its parent
classloader. So could you guys please tell me what's wrong?
Thanks
-- 
anfernee

Re: The AntClassLoader created in one JUnitTask can not be used in another.

[Steve Loughran <st...@apache.org>]

Xu Xin wrote:
> Hello everyone,
> 
> I had a problem with JUnitTask, I have a couple of xml files where I also
> have a lot of targets which contain <junit> tasks, originally I used the
> Apache Ant's JUnitTask, but unfortunately the test run had performance
> issue, that was caused by  each <test> has its own classloader, as a result
> some static memory was created multiple times.
> 
> So I customized the JUnitTask by making the classloader created for each
> test cacheable, the <junit> task has the same customer classpath elements
> share the same classloader, so I can save the memory as I can, but the
> strange thing is  junit testcase was not recognized, it seemed a
> classloading issue, but after I ran the tests in DEBUG mode, I can find the
> classloader hierarchy is correct, I do not know what's going wrong. The
> snippet code is below:
> 
> 

> 
> and next pass the classLoader to JUnitTestRunner as usual, the test class
> can be loaded, as well as JUnit class: TestSuite and Test, but when
> constructing TestCase, TestSuite complains the test class is not
> implementation of Test, but I can see the test class was loaded by cached
> AntClassLoader, and TestSuite and Test were loaded by its parent
> classloader. So could you guys please tell me what's wrong?
> Thanks


My recommendation would be to avoid these things; its very easy to leak 
classes by sharing a classloader.

Just fork the junit run with fork="once" in your <junit> task

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