How can we define global variables in java

Question

I want to call the variables from anywhere, for which I need to declare them as global. How to do that?

Answer 1

To make the variable as global , you can use the keyword static:

public class Global

{
    public static int x;
    public static int y;
}

Answer 2

You could create a set of public static members in a class named Globals.

public class Globals {
   public static int globalInt = 0;
   ///
}

Answer 3

Another way is to create an interface like this:

public interface GlobalConstants
{
  String name = "Chilly Billy";
  String address = "10 Chicken head Lane";
}

Any class that needs to use them only has to implement the interface:

public class GlobalImpl implements GlobalConstants
{
  public GlobalImpl()
  {
     System.out.println(name);
  }
}

Answer 4

class G {
  static String globalVar = "Global Value";
}

class Class1 {
  Class1() {
    System.out.println("Class1: "+G.globalVar);
    G.globalVar += " - changed";
} }
class Class2 {
  Class2() {
    System.out.println("Class2: "+G.globalVar);
} }

class Main {  
  public static void main(String[] args) {  
    Class1 o1 = new Class1();
    Class2 o2 = new Class2();
} }

/*
Output:
Class1: Global Value
Class2: Global Value - changed
*/

Answer 5

Global variables are not technically allowed in Java. A global variable is one declared at the start of the code and is accessible to all parts of the program. Since Java is object-oriented, everything is part of a class. ... A static variable can be declared, which can be available to all instances of a class.

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Answer 6

To define Global Variable you can make use of static Keyword

public class Example {
    public static int a;
    public static int b;
}

now you can access a and b from anywhere by calling

Example.a;

Example.b;