What is the purpose of the method public static void main in a Java program? What is the difference between System.out.println and System.err.println? What is an interface in Java? When would you use an abstract class instead of an interface? What are the differences between a public method and a protected one? What is a static variable? What is an Exception in Java? Is it a good practice to catch a RuntimeException?

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Answers to common Java interview questions

public static void main is the entry point of a Java program
System.out.println prints to standard output while System.err.println prints to standard error
An interface is a collection of abstract methods that can be implemented by a class
Use an abstract class when you want to provide a default implementation or when you need to inherit from multiple classes
Public methods can be accessed from anywhere while protected methods can only be accessed within the same package or by subclasses
A static variable is a variable that belongs to the class and not to any instance of the class
An Exception is an object that represents an error or unexpected condition in a program
It depends on the situation, but generally it's better to fix the root cause of the RuntimeException instead of catching it