Exam Questions and CORRECT Answers
keywords - CORRECT ANSWER - class, while and if are....
primitive types - CORRECT ANSWER - which are simple values stored directly in the
memory location
reference types - CORRECT ANSWER - which store addresses of objects stored
somewhere else in memory
static - CORRECT ANSWER - methods not associated with any object
instance - CORRECT ANSWER - methods are part of objects and can only be called
through an object
What are the two general ways of accessing a Java array? - CORRECT ANSWER - direct
access and sequential access
direct access - CORRECT ANSWER - accessing an arbitrary location
sequential access - CORRECT ANSWER - going through the entire array
compiler/syntax errors - CORRECT ANSWER - prevent program from being compiled
properly,
forgetting semicolon or braces
, logic errors - CORRECT ANSWER - are problems with what the code actually does, like
forgetting braces around else, so the code doesn't know what to do with else
Data hiding - CORRECT ANSWER - when an object hides its internal data from code
outside the class that the object
//is an instance of. Only the class can access its own methods. Make fields private and methods
public
data abstraction - CORRECT ANSWER - using a class without knowing its
implementation Details
differences between array and arraylist - CORRECT ANSWER - - Array is a fixed length
data structure
- arraylist- You can not change length of Array once created in Java but ArrayList re-size itself
when gets full depending upon capacity and load factor.
-one more major difference between ArrayList and Array is that, you can not store primitives in
ArrayList, it can only contain Objects. While Array can contain both primitives and Objects in
Java
infinite loops - CORRECT ANSWER - -loop that never terminates, the test condition is
always true if nothing is done to change the condition within the loop body
Inheritance - CORRECT ANSWER - - Properties of a data type can be passed down to a
sub-type
Polymorphism - CORRECT ANSWER - - Operations used with a variable are based on
the class of the object being accessed, not the class of the variable
we can use an arrayList without having to know whether its implemented true or false? -
CORRECT ANSWER - true