How many types of scopes are there in Java?

How many types of scopes are there in Java?

I'd be happy to respond in English for this question.

In Java, a scope refers to the region of the code where a variable is accessible. The type of scope in Java can be classified into several categories:

public class Myclass {
int x; // has package scope
public static void main(String[] args) {
Myclass my = new Myclass();
System.out.println(my.x);  // ok, because it's in the same package
}
}

public class MyClass {
public int x;  // has public scope
public static void main(String[] args) {
MyClass my = new MyClass();
System.out.println(my.x);  // ok, because it's public
}
}

public class MyClass {
private int x;  // has private scope
public void display() {
System.out.println(x);
}
public static void main(String[] args) {
MyClass my = new MyClass();
System.out.println(my.x);  // error, because it's private
}
}

public class MyClass {
protected int x;  // has protected scope
public void display() {
System.out.println(x);
}
public static void main(String[] args) {
MyClass my = new MyClass();
System.out.println(my.x);  // ok, because it's in the same package
}
}
public class MySubClass extends MyClass {
public static void main(String[] args) {
MySubClass submy = new MySubClass();
System.out.println(submy.x);  // ok, because it's protected and it's a subclass
}
}

In summary, the four types of scope in Java are package-private, public, private, and protected. Understanding these scopes is crucial for designing classes, methods, and variables that work together effectively.

Please let me know if you have any further questions or concerns!

How to check the scope of a variable in Java?

I'd be happy to help!

In Java, you can use several methods to determine the scope of a variable:

Example:

public class MyStaticClass {
public static int myStaticVariable = 0;
public void printStatic() {
System.out.println(myStaticVariable); // prints 0
}
}

Example:

public class MyBlockClass {
public void myMethod() {
if (true) {
int myLocalVariable = 5; // accessible here
System.out.println(myLocalVariable); // prints 5
}
}
}

Example:

public class MyMethodClass {
public void myMethod() {
int myLocalVariable = 0; // accessible here
System.out.println(myLocalVariable); // prints 0
}
}

Example:

public class MyLambdaClass {
public void myMethod() {
IntFunction intFunc = () -> {
int myLocalVariable = 5; // accessible here
System.out.println(myLocalVariable); // prints 5
};
}
}

Example:

public class MyAnonymousClass {
public void myMethod() {
new Runnable() {
@Override
public void run() {
int myLocalVariable = 0; // accessible here
System.out.println(myLocalVariable); // prints 0
}
};
}
}

In summary, Java has several ways to define the scope of a variable:

I hope this helps!