What is the internal structure of a class and what elements does it consist of?

The internal structure of a class in Java consists of several key elements:

• Fields (instance variables) — store the state of the object.
• Methods — define the behavior of the object, implement logic.
• Constructors — special methods for initializing new objects.
• Static blocks and fields — shared among all instances of the class.
• Nested classes and interfaces — classes declared within another class.
• Metadata (annotations) — additional information for the compiler or at runtime.

At the bytecode level, a class is represented as a .class file, which contains:

• A header with version and class information.
• The constant pool — a table of constants used in the class.
• Descriptions of fields and methods.
• Attributes (e.g., debug information, annotations).

Thus, a class is a collection of data and methods organized to describe an object and its behavior.