Java Programming Basics What is jar in Java What is the difference between an abstract class and an interface? How do you derive a new class from a class? Given an interface, how would you make your class behave like the interface. What are some advantages of all classes deriving from a common class like Object? What are some methods defined in the Object class and how are they useful? What does the default toString() method implementation do? What are primitive wrapper classes? What is the difference between constructors and other methods? What is a static method? Why would you declare a class final? What are the four types of nested classes? What is an abstract class? Where would you use the keyword extends and implements? How do you call a constructor of a super class? Where would you call it? How do you call a method in a super class from a subclass? How are parameters passed in Java, by value or by reference? What restrictions are placed on method overloading? How are this() and super() used with constructors? Advantage of using Java? What are the differences between C++ and Java? Explain working of Java Virtual Machine (JVM)? What is reflection API? How are they implemented? What is transient variable? What modifiers are allowed for methods in an Interface? What is a local, member and a class variable? What does it mean that a method or field is “static”? What are wrapped classes? What are the usages of Java packages? What is Java Serial Version ID? What is difference between JDK,JRE and JVM? How many types of memory areas are allocated by JVM? What is JIT compiler? What is the main difference between Java platform and other platforms? What gives Java its ‘write once and run anywhere’ nature? What is classloader? If I don’t provide any arguments on the command line, then the String array of Main method will be empty or null? What if I write static public void instead of public static void? What is the default value of the local variables? What is an immutable object? Expain the reason for each keyword of public static void main(String args)? What are the differences between == and .equals() ? What if the static modifier is removed from the signature of the main method? What is the difference between final, finally and finalize? What do you understand by the java final keyword? What is the Java API? Why there are no global variables in Java? How to convert String to Number in java program? What is implicit casting? In System.out.println(), what is System, out and println? What is a native method?