Correct Answer: new ClassName( arg1, arg2, argN); Ex: Class sample { Sample(int a) { Systemoutprintln("arg con a =" +a); } } class Demo { Public static void main( String[] args) { Sample s1= new Sample(23); Sample s2= new Sample(45); } }
2. What is different among String, StringBuffer, StringBuilder?
Correct Answer: String class objects are immutable objects and they represents strings( sequence of characters) StringBuffer class objects are mutable objects representing strings and they are Thread safe StringBuild class objects are also mutable objects representing strings and they are not Thread safe
Correct Answer: Wrapping is also called as packing or boxing Storing the data inside the object as private data which can accessed outside the class only by using methods
Correct Answer: Unwrapping is also called as unpacking or unboxing Getting the private data stored in the object by using methods is called unpacking or unwrapping
5. What is JAR file? what are the main uses of JAR files?
Correct Answer: JAR files are java's version of ZIP files In fact, JAR uses the ZIP file format uses: - to compress a number of class files into one file - to make a java executable JAR file
6. What is the difference between path and classpath?
Correct Answer: - By using method overriding a sub class can change the definition of super class method - By using overriding a sub class can modify the functionality of the super class
10. What is the use of overloading ? or why overloading?