Systems and methods for loading modified classes into a running application

A system for dynamically updating classes in a running application, comprising:

• at least one memory;
• and
• at least one hardware processor coupled with the at least one memory and configured, individually or in combination, to:
• identify an application running within a virtual machine (VM);
• generate, within the application, a patcher thread for processing patches, wherein the patcher thread is set as a daemon thread and is distinct from a listener thread;
• instantiate, within the application, a patcher class using a singleton pattern to prevent the patcher class from being instantiated multiple times;
• install a shutdown hook in the VM to signal the patcher thread to stop operation and release resources during termination of the application;
• generate a notification that a live patching facility is set up using a system property in the VM;
• detect, via the patcher thread, a task to replace an existing version of a class with an updated version of the class at runtime by periodically scanning, using a polling technique, a local file system tasks directory for new class files, wherein each class file in the tasks directory has a name corresponding to a fully qualified name of a target class, and wherein finding the updated version of the class comprises determining that the class file has not been previously applied or that a modification timestamp of the class file is greater than a last recorded modification timestamp for the target class maintained in a registry of applied class files;
• and
• execute, by the patcher thread, the task to replace the existing version of the class with the updated version.

A non-transitory computer readable medium storing thereon computer executable instructions for dynamically updating classes in a running application, including instructions for:

• identifying an application running within a virtual machine (VM);
• generating, within the application, a patcher thread for processing patches, wherein the patcher thread is set as a daemon thread and is distinct from a listener thread;
• instantiating, within the application, a patcher class using a singleton pattern to prevent the patcher class from being instantiated multiple times;
• installing a shutdown hook in the VM to signal the patcher thread to stop operation and release resources during termination of the application;
• generating a notification that a live patching facility is set up using a system property in the VM;
• detecting, via the patcher thread, a task to replace an existing version of a class with an updated version of the class at runtime by periodically scanning, using a polling technique, a local file system tasks directory for new class files, wherein each class file in the tasks directory has a name corresponding to a fully qualified name of a target class, and wherein finding the updated version of the class comprises determining that the class file has not been previously applied or that a modification timestamp of the class file is greater than a last recorded modification timestamp for the target class maintained in a registry of applied class files;
• and
• executing, by the patcher thread, the task to replace the existing version of the class with the updated version.