Java Language Interview Question and Answers

Java Language Interview Question and Answers

1.	What is Java?
	A high-level programming language developed by Sun Microsystems. Java was originally called OAK, and was designed for handheld devices and set-top boxes. Oak was unsuccessful so in 1995 Sun changed the name to Java and modified the language to take advantage of the burgeoning World Wide Web.

2.	what are the main features of java?
	The main features of java are Compiled and Interpreted Object oriented Robust and secure Type safe High Performance.

3.	What are pass by reference and passby value?
	Pass By Reference means the passing the address itself rather than passing the value. Passby Value means passing a copy of the value to be passed.

4.	What is the Java API?
	The Java API is a large collection of ready-made software components that provide many useful capabilities, such as graphical user interface (GUI) widgets.

5.

What is the Java Virtual Machine (JVM)?

The Java Virtual Machine is software that can be ported onto various hardware-based platforms. 6. What is variables and then types? Variables is an identifier that denotes a storage location used to store a data values.unlike constants that remain unchanged during the execution of a program, a variable may takes different values at different times during the execution of the program. Instance variables Class variables Local variable Parameters 7. what is dot operator? The dot operator(.) is used to access the instance variables and methods of class objects.It is also used to access classes and sub-packages from a package. Examples :  Person1.age ---------> Reference to the variable age 8. Define strings? Strings represent a sequence of characters.The easiest way to represent a sequence of characters in java is by using a character array. 9. What is serialization? Serialization is the process of converting a objects into a stream of bytes. 10. What are different types of access modifiers? Access specifiers are keywords that determine the type of access to the member a class. Public Protected Private Default