Can we declare a method as private in Java?

Yes, we can declare the main method as private in Java. It compiles successfully without any errors but at the runtime, it says that the main method is not public.

Can we make method as private?

Certainly you can define a method as private , so that it can only be called (essentially) from other methods in the same class. This is a pretty common practice.

When a method is declared as private?

The 'private' access modifier is the one that has the lowest accessibility level. The methods and fields that are declared as private are not accessible outside the class. They are accessible only within the class which has these private entities as its members.

What will happen if we declare main method as private in Java?

But if you declare main method as private, you would not be able to execute the class as a standalone java program. Any java class that needs to be executed as a standalone file needs to have a main method that is public, static and returns a void.

When should methods be private in Java?

The rule is that a method should be made provided unless it is needed. One of the main reasons for this is that in a future release of an API etc., you can always make a private function public, but you can almost never make a previous public function private without breaking existing code.

Java Access Modifiers - Learn Public, Private, Protected and Default

Are methods always public in Java?

All abstract, default, and static methods in an interface are implicitly public , so you can omit the public modifier. In addition, an interface can contain constant declarations. All constant values defined in an interface are implicitly public , static , and final .

Why methods should be private?

Private methods are useful for breaking tasks up into smaller parts, or for preventing duplication of code which is needed often by other methods in a class, but should not be called outside of that class.

Can we declare main () method as non static?

You can write the main method in your program without the static modifier, the program gets compiled without compilation errors. But, at the time of execution JVM does not consider this new method (without static) as the entry point of the program.

Can main method be static?

Java main() method is always static, so that compiler can call it without the creation of an object or before the creation of an object of the class. In any Java program, the main() method is the starting point from where compiler starts program execution. So, the compiler needs to call the main() method.

Can we override static method?

Overloading is the mechanism of binding the method call with the method body dynamically based on the parameters passed to the method call. Static methods are bonded at compile time using static binding. Therefore, we cannot override static methods in Java.

Is private method are final?

So, to answer question 2, yes, all compilers will treat private methods as final . The compiler will not allow any private method to be overridden. Likewise, all compilers will prevent subclasses from overriding final methods.

Can private method be overloaded?

Yes, we can overload private methods in Java but, you can access these from the same class.

Is overriding possible in Java?

In Java, method overriding occurs when a subclass (child class) has the same method as the parent class. In other words, method overriding occurs when a subclass provides a particular implementation of a method declared by one of its parent classes.

Can we execute a program without main?

Yes, we can execute a java program without a main method by using a static block. Static block in Java is a group of statements that gets executed only once when the class is loaded into the memory by Java ClassLoader, It is also known as a static initialization block.

Can we overload main method?

Yes, we can overload the main method in Java, but When we execute the class JVM starts execution with public static void main(String[] args) method.

Can we write method without class in Java?

No you cannot make a java program without class! Because without a class you cannot make objects!

Why main () method is declared as static?

The main() method is static so that JVM can invoke it without instantiating the class. This also saves the unnecessary wastage of memory which would have been used by the object declared only for calling the main() method by the JVM.

Can we write main method without void?

Yes. Things like libraries don't have a main method. The main method is the entry point for the program, so you'll have to have a main method somewhere or the code won't execute, but not necessarily in any given Java file.

Why testing private methods is bad?

In short, testing private functions (by using FRIEND_TEST or making them public or using reflection) that could otherwise be tested through a public interface can cause test duplication. You really don't want this, because nothing hurts more than your test suite slowing you down.

Can a private method call a public method?

If a private method must call a public method, then the content of the public method should be taken and placed in a private method, which both methods can then call. Why? The public method may contain tests that aren't necessary once your executing code internally.

Should I mock private methods?

Mocking techniques should be applied to the external dependencies of the class and not to the class itself. If mocking of private methods is essential for testing our classes, it usually indicates a bad design.

Can a method be abstract?

A method without body (no implementation) is known as abstract method. A method must always be declared in an abstract class, or in other words you can say that if a class has an abstract method, it should be declared abstract as well.

Why methods are public in Java?

public is a Java keyword which declares a member's access as public. Public members are visible to all other classes. This means that any other class can access a public field or method. Further, other classes can modify public fields unless the field is declared as final .

Can interface methods private?

An interface can have private methods since Java 9 version. These methods are visible only inside the class/interface, so it's recommended to use private methods for confidential code.

Can constructor be overloaded?

Constructors can be overloaded in a similar way as function overloading. Overloaded constructors have the same name (name of the class) but the different number of arguments. Depending upon the number and type of arguments passed, the corresponding constructor is called.