WHY JAVA SUITABLE FOR INTERNET
Due to two reasons they are 1. It is system
independent and hence its programs can run on any type of computer available on
internet 2. It has security to save data , it eliminates a lot of security
problems for data on internet.
WHY POINTERS ARE ELIMINATED FROM JAVA
1. Pointer
s lead to confusion to the programmer
2. Pointers
break the security. Using pointers harmful programs like virus and other
hacking programs are developed
WHAT IS THE DIFFERENCE BETWEEEN FUCTION AND METHOD
Both
are same but in java functions are called as methods, and in java every method
should be written inside a class only. But in c++ functions
can be write inside or outside the class.
WHICH ALGORITHM IS USED BY GARBAGE COLLECTOR
Mark
and sweep algorithm
HOW CAN WE CALL GARBADE COLLECTOR
Calling
gc() method of Runtime class or System class in java
WHAT IS JIT COMPLIER
JIT
compiler is a part of JVM which increases the speed of a java program
WHAT IS AN API DOCUMENT
An
api document is a .html file which contains description of all features of a
software, product or technology
WHAT IS THE DIFFERENCE BETWEEN #include and import STATEMENTS
#include
makes the compiler to go to standard library and copy the ode from the header
file into the program. As a result the program size will increase.
Import
statement makes the JVM to go to standard library and execute the code of header
file their itself and substitute the
result. Thereby the program size doesn’t change.
WHAT HAPPENS IF String args[] is not written in main()
The
program will be compiled but JVM cannot run the program. To run any java
program JVM should identify main() and start execute from main(). If we don’t write
String args[] then JVM cant identify main() hence program cant be executed.
WHAT IS THE DIFFERENCE BETWEEN print() and println()
If
we use print the JVM will print the message
If
we use println() the JVM will print the message and cursor will come to next
line.
WHAT IS THE DIFFERENCE BETWEEN FLOAT AND DOUBLE
Float
can represent upto 7 decimals 1.1234567
Double
can represent upto 15 decimals 1.123456789123456
WHAT IS UNICODE SYSTEM
Unicode
is encoding standard which provides an unique number for every character no
matter which language it is.
HOW POSITIVE AND NEGATIVE NUMBERS ARE REPRESENTED IN SYSTEM
+ve
by 1’s compliment, _ve by 2’s compliment
OUT OF DO WHILE AND WHILE WHICH IS EFFICIENT
While
loop is efficient because. Consider do while it doesn’t checks condition for
first time. But while will check the condition from starting onwards. So while
is efficient than do while loop
WHY GOTO STATEMENT IS NOT PRESENT IN JAVA
Goto
statement leads to confusion for the programmer. Especially in large programs
WHAT IS DIFFERENCE BETWEEN return, System.exit(0), System.exit(1)
RETURN
used to come out of method
System.exit(0)
used to come out of program i.e., normal termination
System.exit(1)
used to come out of program i.e.. When some error occurs
WHAT IS THE DIFFERENCE BETWEEN System.out and System.err
System.out
used to display noramal messages on monitor
System.err
used to display error messages on
monitor
ON WHICH MEMORY ARRAYS WERE CREATED IN JAVA
Not
only arrays every thing is created dynamically in java, so no wastage of memory
in java
CAN YOU CALL main() METHOD FROM ANOTHER CLASS
Yes
we can call main() of one class in another class by using its calss name
Classname.main()
IS STRING IS A CLASS OR DATATYPE IN JAVA
String
is a class present in java.lang package
CAN WE CALL CLASS AS DATATYPE
Yes
we can call a class as datatype because it is defined by user so it can be
called as user defined data type
WHAT IS OBJECT REFERENCE
Object
reference is an hexadecimal value representing the memory address of object
WHAT IS THE DIFFERENCE BETWEEN == AND equals() WHILE COMPARING
STRINGS
==
operator compares the references of the string object but it doesn’t compare the
content in them. But equals() will
compare contents too.
WHAT IS A STRING CONSTANT POOL
String
constant pool is another memory block where jvm stores all the string objects.
String
s1=”hello”. Now s1 is stored in string constant pool
WHAT IS THE DIFFERENCE BETWEEN STRING AND STRINGBUFFER CLASS
String
class objects are immutable i.e. their contents can’t be changed or modified
StringBuffer
class objects are mutable i.e., their contents can be modified
WHAT IS THE DIFFERENCE BETWEEN Stringbuffer and StringBuilder
CLASSES
StringBuffer
class in synchronized and StringBuilder is not
WHAT IS OBJECT ORIENTED APPROACH
To
design computer programs using classes and objects is known as object oriented approach
WHAT IS CLASS AND OBJECT
A
class is a user defined or a class is
collection of data members and member functions or a calss is blueprint
An
object is real time entity
Class—blue
print of building
Object—real
building after construction
WHAT IS THE DIFFERENCE BETWEEN OOP AND OBJECT BASED
Both
are same but inheritance is present in OOPS
but it is not present in object based programming
OOPS- JAVA, SMALLTALK,C++
Object
based: JavaScript, VB Script, and Action Script
WHAT IS HASH CODE
Hash
code is a unique number allocate to objects by JVM
MyClass
mc=new MyClass();
mc.hashCode()
CAN WE DECLARE A CLASS AS PRIVATE
No
we cant declare a calss as private. If we declare a class as private then JVM
during execution cant have permission to execute/ access the class
WHEN IS CONSTRUCTOR CALLED BEFORE OR AFTER CREATING OBJECT
Constructor
is called concurrently when object is created
WHAT IS CONSTRUCTOR OVERLOADING
Writing
two or more constructors with the same name but different paramenters is called
as constructor overloading.
REMAINING WITH IN COUPLE
OF DAYS STAY TUNED
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