What is the use of Custom Class Loader

java classloader
Priyank Doshi picture Priyank Doshi · May 31, 2012 · Viewed 12k times · Source

Recently I came accross the java custom class loader api. I found one use over here, kamranzafar's blog I am a bit new to the class loader concept. Can any one explain in detail, what are the different scenarios where we may need it or we should use it?

Answer

Ramesh PVK picture Ramesh PVK · May 31, 2012

Custom class loaders are useful in larger architectures consisting of several module/applications. Here are the advantages of the custom class loader:

  • Provides Modular architecture Allows to define multiple class loader allowing modular architecture.
  • Avoiding conflicts Clearly defines the scope of the class to within the class loader.
  • Support Versioning Supports different versions of class within same VM for different modules.
  • Better Memory Management Unused modules can be removed which unloads the classes used by that module, which cleans up memory.
  • Load classes from anywhere Classes can be loaded from anywhere, for ex, Database, Networks, or even define it on the fly.
  • Add resources or classes dynamically All the above features allows you add classes or resources dynamically.
  • Runtime Reloading Modified Classes Allows you to reload a class or classes runtime by creating a child class loader to the actual class loader, which contains the modified classes.

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