Move ShutdownHelper to agent-bootstrap… #3913
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…nto the bootstrap classloader later on.
Types under agent-bootstrap are automatically made available from the bootclasspath as part of installing the javaagent.
This avoids the need to register them as helper classes via HelperInjector. It is especially important to avoid using
HelperInjector when instrumentating JDK classes because the only way we can inject types into the bootclasspath after
the javaagent has been installed is to use a temporary jar file (unfortunately the only approach allowed by the JVM's
instrumentation API)
Use of a temporary jar file causes issues in serverless environments, but it's worse when instrumenting j.l.Shutdown
because we use File.deleteOnExit to attempt to clean up these temporary jars when the process ends (we cannot remove
them while the JVM is alive because of how the JVM maps the classes into memory) and File.deleteOnExit interacts with
j.l.Shutdown to register its own shutdown hook.
This results in an exception while trying to inject the helper which then leads to the following exception at shutdown:
Exception in thread "main" java.lang.NoClassDefFoundError: Could not initialize class java.io.DeleteOnExitHook
at java.io.File.deleteOnExit(Unknown Source)
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…nto the bootstrap classloader later on. (#3913) Types under agent-bootstrap are automatically made available from the bootclasspath as part of installing the javaagent. This avoids the need to register them as helper classes via HelperInjector. It is especially important to avoid using HelperInjector when instrumentating JDK classes because the only way we can inject types into the bootclasspath after the javaagent has been installed is to use a temporary jar file (unfortunately the only approach allowed by the JVM's instrumentation API) Use of a temporary jar file causes issues in serverless environments, but it's worse when instrumenting j.l.Shutdown because we use File.deleteOnExit to attempt to clean up these temporary jars when the process ends (we cannot remove them while the JVM is alive because of how the JVM maps the classes into memory) and File.deleteOnExit interacts with j.l.Shutdown to register its own shutdown hook. This results in an exception while trying to inject the helper which then leads to the following exception at shutdown: Exception in thread "main" java.lang.NoClassDefFoundError: Could not initialize class java.io.DeleteOnExitHook at java.io.File.deleteOnExit(Unknown Source)
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…to avoid having to inject it into the bootstrap classloader later on.
Types under agent-bootstrap are automatically made available from the bootclasspath as part of installing the javaagent.
This avoids the need to register them as helper classes via HelperInjector. It is especially important to avoid using HelperInjector when instrumentating JDK classes because the only way we can inject types into the bootclasspath after the javaagent has been installed is to use a temporary jar file (unfortunately the only approach allowed by the JVM's instrumentation API)
Use of a temporary jar file causes issues in serverless environments, but it's worse when instrumenting j.l.Shutdown because we use File.deleteOnExit to attempt to clean up these temporary jars when the process ends (we cannot remove them while the JVM is alive because of how the JVM maps the classes into memory) and File.deleteOnExit interacts with j.l.Shutdown to register its own shutdown hook.
This results in an exception while trying to inject the helper
which then leads to the following exception at shutdown: