Computer Science Java Questions with
Detailed Verified Answers for Accuracy
keywords
✓✓ class, while and if are....
primitive types
✓✓ which are simple values stored directly in the memory location
reference types
✓✓ which store addresses of objects stored somewhere else in
memory
static
✓✓ methods not associated with any object
instance
✓✓ methods are part of objects and can only be called through an
object
What are the two general ways of accessing a Java array?
✓✓ direct access and sequential access
direct access
pg. 1
,✓✓ accessing an arbitrary location
sequential access
✓✓ going through the entire array
compiler/syntax errors
✓✓ prevent program from being compiled properly,
forgetting semicolon or braces
logic errors
✓✓ 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
✓✓ 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
✓✓ using a class without knowing its implementation Details
differences between array and arraylist
pg. 2
, ✓✓ - 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
✓✓ -loop that never terminates, the test condition is always true if
nothing is done to change the condition within the loop body
Inheritance
✓✓ - Properties of a data type can be passed down to a sub-type
Polymorphism
✓✓ - 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?
pg. 3
Detailed Verified Answers for Accuracy
keywords
✓✓ class, while and if are....
primitive types
✓✓ which are simple values stored directly in the memory location
reference types
✓✓ which store addresses of objects stored somewhere else in
memory
static
✓✓ methods not associated with any object
instance
✓✓ methods are part of objects and can only be called through an
object
What are the two general ways of accessing a Java array?
✓✓ direct access and sequential access
direct access
pg. 1
,✓✓ accessing an arbitrary location
sequential access
✓✓ going through the entire array
compiler/syntax errors
✓✓ prevent program from being compiled properly,
forgetting semicolon or braces
logic errors
✓✓ 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
✓✓ 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
✓✓ using a class without knowing its implementation Details
differences between array and arraylist
pg. 2
, ✓✓ - 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
✓✓ -loop that never terminates, the test condition is always true if
nothing is done to change the condition within the loop body
Inheritance
✓✓ - Properties of a data type can be passed down to a sub-type
Polymorphism
✓✓ - 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?
pg. 3
