What is the role and purpose of the ClassLoader mechanism in Java?

ClassLoader in Java is responsible for the dynamic loading of classes into the JVM during program execution. Its main role is to find and load the bytecode of classes from various sources (file system, network, JAR archives, etc.) so that JVM can use them.

Purpose of ClassLoader:

• Class isolation: different loaders can load different versions of the same class.
• Support for dynamic loading: classes are loaded as needed, saving resources.
• Extensibility: custom loaders can be created to load classes from non-standard sources.

Example: when you create an object of a new class, JVM via ClassLoader searches and loads the corresponding .class file if it is not already loaded.