spring-boot

Spring Boot

Andy Wilkinson 87fe0b2ade Use a conventional delegation model in LaunchedURLClassLoader When an application is run as an executable archive with nested jars, the application's own classes need to be able to load classes from within the nested jars. This means that the application's classes need to be loaded by the same class loader as is used for the nested jars. When an application is launched with java -jar the contents of the jar are on the class path of the app class loader, which is the parent of the LaunchedURLClassLoader that is used to load classes from within the nested jars. If the root of the jar includes the application's classes, they would be loaded by the app class loader and, therefore, would not be able to load classes from within the nested jars. Previously, this problem was resolved by LaunchedURLClassLoader being created with a copy of all of the app class laoder's URLs and by using an unconventional delegation model that caused it to skip its parent (the app class loader) and jump straight to its root class loader. This ensured that the LaunchedURLClassLoader would load both the application's own classes and those from within any nested jars. Unfortunately, this unusual delegation model has proved to be problematic. We have seen and worked around some problems with Java Agents (see gh-4911 and gh-863), but there are others (see gh-4868) that cannot be made to work with the current delegation model. This commit reworks LaunchedURLClassLoader to use a conventional delegate model with the app class loader as its parent. With this change in place, the application's own classes need to be hidden from the app class loader via some other means. This is now achieved by packaging application classes in BOOT-INF/classes (and, for symmetry, nested jars are now packaged in BOOT-INF/lib). Both the JarLauncher and the PropertiesLauncher (which supports the executable jar layout) have been updated to look for classes and nested jars in these new locations. Closes gh-4897 Fixes gh-4868		10 years ago
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samples	Polishing	10 years ago
src	Use a conventional delegation model in LaunchedURLClassLoader	10 years ago
test-samples	Add value alias for SpringApplicationConfiguration	11 years ago
pom.xml	Use a conventional delegation model in LaunchedURLClassLoader	10 years ago