1.13 Scope

The scope of a variable determines for what space it is visible.

• Variables declared at the beginning of a method are visible throughout the method.
• Variables declared globally are visible anywhere in the class.
• When the name of a local variable is the same as a global variable, then local variable is preferred within the method:

  public class MyScopeClass {   int i = 7;   public void myMethod() {     int i = 9;     // any code referring to i refers to i=9   } }

• Variables declared within a block denoted by curly brackets {} are only visible within that block. This affects loops as well as any other bracketed expression:

  ... int x = 5; for (int y = 0; y < 10; y++) {   // x, y are visible } // only x is visible ...

• Even though brackets define a new scope, variables of a given name cannot be re-declared:

  ... int x = 9; while (true) {   int x = 3;  // this causes compiler errors } ...