What is scope in programming?

Scope defines the accessibility of a variable, method, or class within a certain part of the program. It controls where named entities can be used and where they cease to exist.

In Java, the main scopes are:

• Block: Limited by a pair of curly braces {}. Variables declared inside the block are accessible only within this block and its nested blocks.
• Method: Limited by the method body. Parameters and variables declared inside the method are accessible only within this method.
• Class: Limited by the class body. Member variables (fields) and methods are accessible from anywhere within the class. Their accessibility outside the class depends on access modifiers (public, private, protected, default).
• Package: Applies to classes and class members (without access modifier). Accessible anywhere within the same package.
• Global: Java does not have a truly global scope like in C++. The closest equivalent is public static final fields in classes, accessible throughout the program.

Example of block scope:

// Variable 'j' is not visible outside this block
{
    int j = 10;
    System.out.println(j); // Accessible
}
// System.out.println(j); // Compilation error: cannot find symbol

Example of method scope:

public void myMethod(int parameter) { // 'parameter' is only visible here
    int localVar = 5; // 'localVar' is only visible here
    System.out.println(parameter); // Accessible
    System.out.println(localVar); // Accessible
}
// System.out.println(localVar); // Compilation error: cannot find symbol

Scope helps prevent naming conflicts, manage variable lifecycle, and improve code readability.