It is not necessary for all the classes to have a main method . main method is used as an entry point for java applications. So once you have entered the java code using main method of a single class you can call other classes code form there.
Does every class need main method?
Yes, it is required for any executable program. If you try to execute a Java class, the JVM will look for a main method to invoke it. ... Not all classes need a main , only the one that serve as “entry point” for execution.
Can a class have a main method?
The main() method can appear in any class that is part of an application , but if the application is a complex containing multiple files, it is common to create a separate class just for main(). The main class can have any name, although typically it will just be called “Main”.
Can a class have no main method?
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 override static method?
Can we override a static method? No, we cannot override static methods because method overriding is based on dynamic binding at runtime and the static methods are bonded using static binding at compile time.
What is main method not found in class?
The main method must be public, static, with return type void, and a String array as argument. You can write a program without defining a main it gets compiled without compilation errors. But when you execute it a run time error is generated saying “Main method not found”.
Can you call a class in Java?
To call a method in Java, write the method name followed by a set of parentheses () , followed by a semicolon ( ; ). A class must have a matching filename ( Main and Main.
How do you call a class inside another class?
Write an inner class in it, return the private members from a method within the inner class, say, getValue(), and finally from another class (from which you want to access the private members) call the getValue() method of the inner class.
Why is Main in a class Java?
By having main() inside a class it is possible to have multiple entry points within a project . i.e. multiple classes with main() methods. This allows you to select a different main class at runtime rather than compile time.
Why the main method is 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 the main method?
No, we cannot override main method of java because a static method cannot be overridden. The static method in java is associated with class whereas the non-static method is associated with an object.
Can you make a constructor final?
No, a constructor can’t be made final . A final method cannot be overridden by any subclasses. As mentioned previously, the final modifier prevents a method from being modified in a subclass. ... In other words, constructors cannot be inherited in Java therefore, there is no need to write final before constructors.
Can we override private method?
No, we cannot override private or static methods in Java. Private methods in Java are not visible to any other class which limits their scope to the class in which they are declared.
Why we Cannot override static method?
Static methods cannot be overridden because they are not dispatched on the object instance at runtime . The compiler decides which method gets called. Static methods can be overloaded (meaning that you can have the same method name for several methods as long as they have different parameter types).
Can a class have private constructor?
Yes. Class can have private constructor . Even abstract class can have private constructor. By making constructor private, we prevent the class from being instantiated as well as subclassing of that class.
Can a Java program run without class?
Yes, you need at least one class to have a program, but no, you do not need any methods (contrary to some other answers). EDIT : From Java 7 the above code with just static block and no main method does not produce any output. Main method is now compulsory. The code with no main method compiles successfully though.
