Local Variable in Java

Let’s learn more about local variables in Java. Variables that are declared inside Methods in a Java program are called local variables.

Rule for Local Variable

• Local variables cannot use any of the access level since their scope is only inside the method.
• Final is the Only Non Access Modifier that can be applied to a local variable.
• Local variables are not assigned a default value, hence they need to be initialized.

Instance Variables are defined at class level.

Example of Local Variable

package com.jbt;

/*
 * Here we will discuss about different type of Variables available in Java
 */
public class VariablesInJava {

  /*
   * Below variable is STATIC variable as it is outside any method and it is
   * using STATIC modifier with it. It is using default access modifier. To
   * know more about ACCESS MODIFIER visit appropriate section
   */
  static String staticField;
  /*
   * Below variable is INSTANCE VARIABLE as it is outside any method and it is
   * not using STATIC modifier with it. It is using default access modifier.
   * To know more about ACCESS MODIFIER visit appropriate section
   */
  int instanceField;

  public static void main(String args[]) {
    VariablesInJava obj = new VariablesInJava();

    /*
     * Instance variable can only be accessed by Object of the class only as below.
     */
    System.out.println(obj.instanceField);

    /*
     * Static field can be accessed in two way.
     * 1- Via Object of the class
     * 2- Via CLASS name
     */
    System.out.println(obj.staticField);
    System.out.println(VariablesInJava.staticField);
  }

  public void method() {
    /*
     * Below variable is LOCAL VARIABLE as it is defined inside method in
     * class. Only modifier that can be applied on local variable is FINAL.
     * To know more about access and non access modifier visit appropriate
     * section.
     *
     * Note* : Local variable needs to initialize before they can be used.
     * Which is not true for Static or Instance variable.
     */
    final String localVariable = "Initial Value";
    System.out.println(localVariable);
  }
}

public class UserController {
  // Instance variable
  private String outsideVariable;

  public void setLength() {

    // Local variable
    String localVariable = "0";

    // In order to use below line local variable needs to be initialzed
    System.out.println("Value of the localVariable is-" + localVariable);
  }
}

Naming Convention

There are no specific rules for naming a local variable. All the rules of variables are applied to local variables.

Below mentioned are the rules for naming a local variable.

• Variable names are case sensitive.
• There is no limitation on the length of a local variable.
• If a variable name is of one word only then all characters should be in lower case.

Bullet Point

• Local variables can not use any of the access levels as they exist inside the Method only.
• The Final is the only nonaccess modifier that can be applied to a local variable.
• Local variables don’t get a default value, hence local variables need to be initiated before they can be used.