Question

Let there be three classes named Tester_1 ,Tester_2,Tester_3. They are defined as :

Tester_1:

class Tester_1 {

 public static void main(String args[]) {
    Tester_2.setBoolean(true);
    System.out.println(Tester_2.getBoolean());
 }
}

Tester_2:

class Tester_2 {

public static boolean var = false; // Static var

public static void setBoolean(boolean value) {
   var = value;
}

public static boolean getBoolean() {
    return var;
}

}

Tester_3:

class Tester_3 {
public static void main(String args[]) {
    System.out.println(Tester_2.getBoolean());
}
}

After I compile all the three classes, I run them in the following order :

java Tester_1

java Tester_3

but I get this output :

true from the first run and false from the second run. Why is that ? When Tester_1 sets the boolean to a value true why do I get the default false when I run Tester_3 ?

Answer 1

static is only valid at the Java Virtual Machine (JVM) level.

Each time you call java xxx you create a new JVM which does not share anything with the previous call => all static variables get their default value again.