Why one public class in one source file in java?

Answer 1

The rules of Java state that the top-level main class needs to be declared "public." The idea behind this is probably because if it was not declared "public," then it would have to be either "private" or "protected." Since these other two types of classes can only be used by classes of the same package (or more local), and thus a non-public main class could not be called from the outside.

Answer 2

A file with .java extension when compiled. The Compiler looks for a unique class file that's declared public. A file cannot have more than one name Similarly in a java file there cannot be more than one public class that is used to uniquely identify the file name but if you try declaring two public class then the compiler throws an error.

Answer 3

So that the class is accessible to all classes that you might code in the application. There are 4 basic access modifiers in java. They are:

1. Public

2. Protected

3. Default and

4. Private

Private is the most restrictive access modifier whereas public is the least restrictive.

If a variable or method is declared public, it means that it can be accessed by anyone or any other class (irrespective of which package they are in). Of course, it is mandatory that the class inside which the public method is placed is visible in the first place for the method or variable to be visible.

Answer 4

A Class can be declared with the following statement:

public class AnandsFirstclass {}

Irrespective of the fact that this class does not have any code, this piece of code when saved in a file called AnandsFirstclass.java compiles just fine. Here public is an access modifier (we will see access modifiers in greater detail in one of the subsequent chapters), class is the keyword that is used to specify that a class is being declared and AnandsFirstclass is the name of the class we are creating.

There are many different types of classes that you can create. Some of which are:

1. Final Classes - A class that cannot be inherited (Dont worry about inheritance just yet. We will look into it in full detail in one of the later chapters)

2. Normal Classes - The type of class that we declared a few lines back

3. Abstract Classes - A class that is similar to a normal class but that does not provide full functional behaviour by itself. It has to be subclassed/inherited in order to be used.

Answer 5

whenever we declare a private class only the members of class can access that function or that class , when ever we declare a class as public it can be access from any where , so it give challenges to security in java .. So we can use protected specifier so that the member of that class and the sub class can use that class....

Answer 6

Declaring an inner class as static tells Java to treat it like a top-level class instead of an inner class.

Answer 7

To use the same class name as file name

Public is the access identifier . Before making a class we need to specify the class visibilty . Hence the precdence.