Java Interview Questions :: Challenging all Java Developers

[neha]

Originally Posted by swati

Next question from my side.

What are wrapper classes in Java?

A primitive wrapper class in the Java programming language is one of eight classes provided in the java.lang package to provide object methods for the eight primitive types. All of the primitive wrapper classes in Java are immutable. J2SE 5.0 introduced autoboxing of primitive types into their wrapper object, and automatic unboxing of the wrapper objects into their primitive value—the implicit conversion between the wrapper objects and primitive values.

Wrapper classes are used to represent primitive values when an Object is required. The wrapper classes are used extensively with Collection classes in the java.util package and with the classes in the java.lang.reflect reflection package.

The primitive wrapper classes and their corresponding primitive types are:

Primitive type Wrapper class Constructor Arguments
byte Byte byte or String
short Short short or String
int Integer int or String
long Long long or String
float Float float, double or String
double Double double or String
char Character char
boolean Boolean boolean or String

The Byte, Short, Integer, Long, Float, and Double wrapper classes are all subclasses of the Number class.

[sumit]

nice answer.

[abhishek]

next question.

What are the advantages of using Spring framework?

[abhishek]

A primitive wrapper class in the Java programming language is one of eight classes provided in the java.lang package to provide object methods for the eight primitive types. All of the primitive wrapper classes in Java are immutable. J2SE 5.0 introduced autoboxing of primitive types into their wrapper object, and automatic unboxing of the wrapper objects into their primitive value—the implicit conversion between the wrapper objects and primitive values.

Wrapper classes are used to represent primitive values when an Object is required. The wrapper classes are used extensively with Collection classes in the java.util package and with the classes in the java.lang.reflect reflection package.

[abhishek]

Next question, what are the differences between doGet and doPost?

[brajesh]

Is this question related to java servlets?

[abhishek]

Yes, now please answer the question..