What is error in the following class definitions? 
abstract class xy { 
abstract sum(int x, int y) {

A. class header is not define properly

B. constructor is no defined

C. method is not defined properly

D. no error

You can do it
  1. When we implement an interface method, it should be declared as public.
  2. A method declared as static can not access non-static class members.
  3. Which javadoc tag is used to denote a comment for methods parameters?
  4. Which of the following control expressions are valid for an if statement?
  5. Every method of a final in class is implicitly final.
  6. One the features of is that an array can store many different types of values.
  7. Which of the following command lines options generates documentation for all classes and methods?
  8. class.forName(...) creates an instance of java ODBC driver
  9. When we implement the Runnable interface, we must define the method
  10. It is perfectly legal to refer to any instance variable inside of a static method.
  11. When we invoke repaint () for a Component, the AWT invokes the method:
  12. Servlet can have ___________
  13. The methods wait() and noify() are defined in
  14. Servlet has ___________
  15. Which of the following statements are valid array declarations?
  16. A panel can not be added to another panel.
  17. With javadoc, which of the following denotes a javadoc comment?
  18. Java always provides a default constructor to a class.
  19. Any class may be inherited by another class in the same package.
  20. A package is a collection of
  21. JdbcOdbcDriver is an object of Object class
  22. We would like to make a member of a class visible in all subclasses regardless of what package they…
  23. If a=10 and b= 15, then the statement x =(a>b)?a:b; assigns the value 15 to x.
  24. Which of the following will produce a value of 10 if x = 9.7?
  25. What does the following line of code do?TextField text=new TextField(10);
  26. JSP files creates ________________
  27. Which of the following statements are true?
  28. Connection, Statement are interfaces and ResultSet is a class.
  29. A class may be both abstract and final.
  30. Declarations can appear anywhere in the body of a Java method.