Java Constants vs Variables: Key Differences

There are several differences between constants and variables in Java when it comes to their usage.

1. Variable worthiness: the value of a constant cannot be changed after initialization, while the value of a variable can be changed.
2. Declaration and initialization: constants must be initialized at the time of declaration and cannot be reassigned; variables can be initialized at the time of declaration or assigned values in subsequent code.
3. Data type: Once constants are declared and initialized, their data type cannot be changed; variables can specify data types at declaration or change data types in subsequent code.
4. Scope: Constants can have either global or local scope, while variables can also have either global or local scope.
5. Naming conventions: Constants are typically named using uppercase letters and underscores, such as PI and MAX_VALUE; variables are usually named using lowercase letters and camel case, such as count and studentName.

In general, the value of a constant cannot be changed during program execution, while the value of a variable can be changed during program execution. Constants are typically used to represent non-changing values, such as mathematical constants, configuration information, etc., while variables are used to represent data that can change.