Java Scope

Java Scope

Scope is where a variable can be seen and used. Variables declared inside a block are only available inside that block.

Block scope

A variable declared inside a block of curly braces exists only there:

public static void main(String[] args) {
  int x = 100; // x can only be used in main

  {
    int y = 50; // y can only be used in this inner block
  }
}

Method parameters

Parameters are local to their method. They exist only while the method runs.

Why scope matters

• Different blocks can reuse the same variable name.
• Variables only live while needed, saving memory.
• Keeps your code organized and predictable.

Naming to avoid confusion

Because of block scope, code like this works:

{
  int x = 100;
}
{
  int x = 200; // fine, this is a different block
}

TL;DR

• Variables only work inside the block where they are declared.
• Curly braces define a block.
• Same names are fine in different blocks.