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1.What
are Java generics?
2.What is
Dynamic Binding?
3.What is
JIT Compiler?
4.What are
Abstract classes?
5.What is
String Tokenizer?
6.What is
Garbage Collector?
7.What is
Inner Class?
8.What is
Anonymous Class?
9.What is
heap in Java?
10.What is
Thread?
11.What is
Daemon Thread?
12.What is
Synchronization?
13.What is
Serialization?
14.How are
memory leaks possible in Java?
15.Can a
method be static and synchronized?
16.What is
better to use: array or vector?
17.Whats
the difference between the two: System.err. and System.out?
When should we use System.err?
1.What are Java generics?
Ans:"Java Generics" is a technical term denoting a set of
language features related to the definition and use of generic
types and methods. Generic types or methods differ from regular
types and methods in that they have type parameters.
2.What is Dynamic
Binding?
Ans:Means the code associated with the given procedure call is
not known until the time of call the call at run time. (it is
associated with Inheritance & Polymorphism).
3.What is JIT Compiler?
Ans: JIT- is a compiler for Byte code, The JIT-Complier is part
of the JVM, it complies byte code into executable code in real
time, piece-by-piece on demand basis.
4.What are Abstract
classes?
Ans:Abstract classes can be used to implement the inheritance
relationship between the classes that belongs same hierarchy.
5.What is String
Tokenizer?
Ans:provide parsing process in which it identifies the
delimiters provided by the user, by default delimiters are
spaces, tab, new line etc., and separates them from the tokens.
Tokens are those which are separated by delimiters.
6.What is Garbage
Collector?
Ans: When an object is no longer referred to by any variable,
java automatically reclaims memory used by that object. This is
known as garbage collection. System.gc() method may be used to
call it explicitly and does not force the garbage collection
but only suggests that the JVM may make an effort to do the
Garbage Collection.
7.What is Inner Class?
Ans:classes defined in other classes, including those defined
in methods are called inner classes. An inner class can have
any accessibility including private.
8.What is Anonymous Class?
Ans:Anonymous class is a class defined inside a method without
a name and is instantiated and declared in the same place and
cannot have explicit constructors.
9.What is heap in Java?
Ans:JAVA is fully Object oriented language. It has two phases
first one is Compilation phase and second one is interpretation
phase. The Compilation phase convert the java file to class
file (byte code is only readable format of JVM) than
Interpretation phase interorate the class file line by line and
give the proper result.
10.What is Thread?
Ans:can be defined as single sequential flow of control with in
a program.
11.What is Daemon Thread?
Ans:Is a low priority thread which runs immediately on the back
ground doing the Garbage Collection operation for the Java Run
time System. SetDaemon( ) – is used to create DaemonThread.
12.What is
Synchronization?
Ans:Two or more threads trying to access the same method at the
same point of time leads to synchronization. If that method is
declared as Synchronized , only one thread can access it at a
time. Another thread can access that method only if the first
thread’s task is completed.
13.What is Serialization?
Ans:The process of writing the state of Object to a byte stream
to transfer over the network is known as Serialization.
14.How are memory leaks
possible in Java?
Ans:If any object variable is still pointing to some object
which is of no use, then JVM will not garbage collect that
object and object will remain in memory creating memory leak.
15.Can a method be static
and synchronized?
Ans:No a static method can't be synchronized.
16.What is better to use:
array or vector?
Ans:Arrays are faster, vectors are more dynamic. This should be
evident just looking at the amount of code you need to traverse
one versus the other.
It might also be beneficial to write a linkedlist class and use
that.
That way you have a dynamic container which has potential to be
faster than a vector (though still not as fast as an array).
The problem with arrays is that if you need more space than the
current size, you have to hardcode their copying into a bigger
array.
17.Whats the difference
between the two: System.err. and System.out? When should we use
System.err?
Ans:System.out leads the output to the standard output stream
(normally mapped to your console screen), System.err leads the
output to the standard error stream (by default the console,
too). The standard output should be used for regular program
output, the standard error for errormessages. If you start your
console program regularly both message types will appear on
your screen.
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