| Previous | Home | Next |
Data types, variables and Arrays
Answer: Variables are locations in memory that can hold values. Before assigning any value to a variable, it must be declared.
Answer: Java has three kinds of variables namely, the instance variable, the local variable and the class variable.
- Local variables are used inside blocks as counters or in methods as temporary variables and are used to store information needed by a single method.
- Instance variables are used to define attributes or the state of a particular object and are used to store information needed by multiple methods in the objects.
- Class variables are global to a class and to all the instances of the class and are useful for communicating between different objects of all the same class or keeping track of global states.
Answer: Variables can be declared anywhere in the method definition and can be initialized during their declaration.
Example:
int i; //declare the variable. i=0; //Initialize the variable
They are commonly declared before usage at the beginning of the definition. Variables with the same data type can be declared together. Local variables must be given a value before usage.
Answer: Variable types can be any data type that java supports, which includes the eight primitive data types, the name of a class or interface and an array.
Answer: Values are assigned to variables using the assignment operator =.
int i=0; int i; i=0;
Answer: A literal represents a value of a certain type where the type describes how that value behaves. There are different types of literals namely number literals, character literals, boolean literals, string literals, etc.
Answer: An array is an object that stores a list of items with same data type.
Answer: Array variable indicates the type of object that the array holds.
int arr[];
(a). True
(b).False
Answer: (b).False
Java Support Array of array. This mean we can assign an array into other to make multidimensional. array.
(a). True
(b).False
Answer: (a). True
Answer: A combination of characters is called as string. The is a String class into lava.lang.* package which is used to wrap any character to make a string.
(a). True
(b).False
Answer: (a). True
Q.13 When a string literal is used in the program, Java automatically creates instances of the string class.
(a). True
(b).False
Answer: (a). True
Answer: Addition operator(+) is used to concatenate strings.
(a). String[ ] s;
(b). String [ ]s:
(c). String[ s]:
(d). String s[ ]:
Answer:
(a). String[ ] s;
(b). String [ ]s:
(d). String s[ ]:
(a). 1
(b). 2
(c). 3
(d). 4
Answer: (d). 4
(a). byte
(b). String
(c). integer
(d). Float
Answer: (a). byte
Explain: String is not primitive data type .It is a String class which is used to string values. Float is not as its capital letter of F. To declare integer primitive values we have int primitive data type in java so it is not good answer.
(a). 0 to 2 16
(b). 0 to 2 15
(c). 0 to 2 16-1
(d). 0 to 2 15-1
Answer: (d). 0 to 2 15-1
Answer: Primitive data types are data type type where we are going to store primtives value(e.g integer, short, float ,double ,long ,character, )There are 8 primitive data type in java. These are
(a). byte, short, int, long
(b). float, double
(c). boolean
(d). char
Answer:
- int: 0
- short: 0
- byte: 0
- long: 0l
- float: 0.0 f
- double: 0.0 d
- boolean: false
- char: '\uoooo'
(a). True
(b). False
Answer: (b). False
Answer: The array subscript expression can be used to change the values of the elements of the array.
Answer: If a variable is declared as final variable, then you can not change its value. It is just like becomes constant.
Answer: Static variables are shared by all instances of a class.
| Previous | Home | Next |