Core Java - Interview Questions and Answers


  1. What are order of precedence and associativity, and how are they used?
    Order of precedence determines the order in which operators are evaluated in expressions. Associatity determines whether an expression is evaluated left-to-right or right-to-left.
  2. Can an anonymous class be declared as implementing an interface and extending a class?
    An anonymous class may implement an interface or extend a superclass, but may not be declared to do both.
  3. What is the range of the char type?
    The range of the char type is 0 to 216 - 1 (i.e. 0 to 65535.)
  4. What is the range of the short type?
    The range of the short type is -(215) to 215 - 1. (i.e. -32,768 to 32,767)
  5. Why isn't there operator overloading?
    Because C++ has proven by example that operator overloading makes code almost impossible to maintain.
  6. What does it mean that a method or field is "static"?
    Static variables and methods are instantiated only once per class. In other words they are class variables, not instance variables. If you change the value of a static variable in a particular object, the value of that variable changes for all instances of that class. Static methods can be referenced with the name of the class rather than the name of a particular object of the class (though that works too). That's how library methods like System.out.println() work. out is a static field in the java.lang.System class.

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