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  1. JDK
  2. JDK-8057936

java.net.URLClassLoader.findClass uses exceptions in control flow

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    Backports

      Description

        If one runs a classloader benchmark:
          http://cr.openjdk.java.net/~shade/8053904/benchmarks.jar

        ...with Nashorn-generated class files:
         http://cr.openjdk.java.net/~shade/8053904/classes.jar

        ...and jdk9 executed as:
         $ java -jar benchmarks.jar -wi 0 -i 30 -r 10s -p file=classes.jar

        ...one can produce this profile:
         http://cr.openjdk.java.net/~shade/8053904/class-install-calltree-java-2.txt

        Looking closely at this profile, one can note a low-hanging fruit: exceptions are frequent. The call tree shows where the exceptions are instantiated. Another view in the profiler shows that a significant amount of time is spend in constructing the stack traces:
         6.670 java.lang.Throwable.fillInStackTrace(int)

        That's 6.6 seconds of total 313 secs of run (around ~2%).
        I think we need to stop doing exceptions there, or at least throw the stackless exceptions.

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            Backport - A issue that is required to port a Bug or Feature into another product release. This issue type is generally associated with the main Bug/Feature to represent each individual release of the port. JDK-8058264 java.net.URLClassLoader.findClass uses exceptions in control flow

            • P4 - Minor loss of function, or other problem where easy workaround is present.
            • Resolved

            Backport - A issue that is required to port a Bug or Feature into another product release. This issue type is generally associated with the main Bug/Feature to represent each individual release of the port. JDK-8063903 java.net.URLClassLoader.findClass uses exceptions in control flow

            • P4 - Minor loss of function, or other problem where easy workaround is present.
            • Resolved

            Backport - A issue that is required to port a Bug or Feature into another product release. This issue type is generally associated with the main Bug/Feature to represent each individual release of the port. JDK-8069987 java.net.URLClassLoader.findClass uses exceptions in control flow

            • P4 - Minor loss of function, or other problem where easy workaround is present.
            • Resolved

            Backport - A issue that is required to port a Bug or Feature into another product release. This issue type is generally associated with the main Bug/Feature to represent each individual release of the port. JDK-8085045 java.net.URLClassLoader.findClass uses exceptions in control flow

            • P4 - Minor loss of function, or other problem where easy workaround is present.
            • Resolved
            relates to

            Enhancement - null JDK-8061244 Use of stack-less ClassNotFoundException thrown from (URL)ClassLoader.findClass()

            • P4 - Minor loss of function, or other problem where easy workaround is present.
            • Open

            Bug - A problem which impairs or prevents the functions of the product. JDK-8055854 Examine overhead in java.net.URLClassLoader

            • P3 - Major loss of function.
            • Closed

            Task - A task that needs to be done. JDK-8053904 JVM Warmup: Investigate class installation overhead

            • P3 - Major loss of function.
            • Closed

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                redestad Claes Redestad
                shade Aleksey Shipilev
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