Java Questions

A static variable in Java belongs to its class and its value remains the same for all its instances. A static variable is initialized when the class is loaded by the JVM. If your code tries to access a non-static variable, without any instance, the compiler will complain, because those variables are not created yet and they are not associated with any instance.

String Args (String []) is an array of parameters of type String.

In Java, 'args' contains the supplied command-line arguments as an array of String objects. In other words, if you run your program as 'java MyProgram Hello World' then 'args' will contain ["Hello", "World"]. When a java class is executed from the console, the main method is what is called.

Final method is a method defined in the super class with final modifier.

We cannot overriding final method of super class in the sub class.

EX:

 Class Sample {

   final void funOne() {

   }

   void funTwo() {

   }

}

Class Sub extends Sample {

  void funOne() { // overriding is not allowed

  }

  viod funTwo() { //overriding is allowed

  }

}

java bean is a reusable component, where as the servlet is the java program which extends the server capability. 

Java uses primitive data types and hence is not a pure object oriented language.

Instance is an object not an attribute

In single virtual machine,JVM passes arguments only by value.

When we create string with new() Operator, it’s created in heap and not added into string pool while String created using literal are created in String pool itself which exists in PermGen area of heap.

String s = new String("Test");

does not put the object in String pool , we need to call String.intern() method which is used to put them into String pool explicitly. its only when you create String object as String literal e.g. String s = "Test" Java automatically put that into String pool.