If a Java agent appends a file to the bootstrap loader using https://docs.oracle.com/javase/10/docs/api/java/lang/instrument/Instrumentation.html#appendToBootstrapClassLoaderSearch(java.util.jar.JarFile), and if the underlying file is marked for deletion using https://docs.oracle.com/javase/7/docs/api/java/io/File.html#deleteOnExit(), the file is not deleted if using Windows.

The problem is that the JVM is holding a handle to the file when the deletion routine is running what prevents the file from being deleted.

This is a problem as many Java agents create temporary files to append classes to the bootstrap loader, thus often polluting the temporary folder of Windows.