Interview Questions Answers in Core Java, JDBC, Advanced Java

Questions / { devarathnam c,kotagudiban }

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Answers / { devarathnam c,kotagudiban }

What is garbage collection in Java, and how can it be used ?

Answer

Hi...
GarbageCollector: Whenever an object is no longer used in
the program at that time the garbage collector reclaims the
memory of an object.It is controlled by the JVM ,The JVM
runs periadically by using "mark" and "sweep"algorithms.
Instead of "destructor" in c++ , java supports garbage
collector.

Is This Answer Correct ?

84 Yes

21 No

Question { Wipro, 14379 }

Differentiate constructor and a method and how are it be
used?

Answer

Hi...
Constructor(): It is also a method but it doesnot allow
return type even void also.It will call automatically
whenever an object is created of a appropriate class.
But class name and constructor should be the same.d
Method():U have to call explicitly .

Is This Answer Correct ?

1 Yes

0 No

Question { Wipro, 17165 }

Java support what type of parameter passing ?

Answer

Hi... By default java supports "pass by value" in case of
primitive datatypes.
In case of objects it supports "pass by references"

Is This Answer Correct ?

8 Yes

4 No

Question { Wipro, 17573 }

Is there is any error if you have multiple main methods in
the same class?

Answer

No error

Is This Answer Correct ?

5 Yes

6 No

Question { TCS, 21972 }

How to initialize an Applet ?

Answer

Hi...
Using public void init();method of the Applet life cycle we
can initialize an applet.

Is This Answer Correct ?

19 Yes

6 No

Question { 8141 }

Can you call a private data from an inner class?

Answer

Yes ,we can call even private data in an inner classes.

Is This Answer Correct ?

0 Yes

4 No

Question { Wipro, 7915 }

What is Type-3 Driver and when this driver is used?

Answer

Type3 Driver:
It is also known as "Net Protocol driver" which is working
based on three-tier system.It requires a middle tire.Mainly
it is used in the "Network environment applications".It
will dependent on one of the application servers like
BEA Weblogic,IBM Websphere etc..

Is This Answer Correct ?

1 Yes

0 No

Question { 6253 }

What is Introspection?

Answer

Hi... Introspectation is the mechanism to analyzing the
bean properties like its size, color,etc.

Is This Answer Correct ?

4 Yes

0 No

Question { Infosys, 7252 }

Explain Object Serialization and it can be used?

Answer

Hi,
Object Serialization: It is process of storing an object
state as permanently in the file(secondary storage).Java is
internet language ,so we need to serialize an object
into "bit-blobs" streams inorder to send an object(s) over
the network.To achieve this task we can use "Serializable"
interface(Marker interface),"ObjectOutputStream"
and "ObjectInputStream" classes also plays key role in the
Serialization process.

Is This Answer Correct ?

6 Yes

0 No

Question { 3240 }

What is a compilation unit?

Answer

Hi...The source code file itself is a compilation unit

Is This Answer Correct ?

0 Yes

0 No

Question { 4455 }

What is a thread?

Answer

Hi...
Thread is a light-weight program ,or it is separate
execution path with in the program.

Is This Answer Correct ?

2 Yes

0 No

Question { 8012 }

What is rmic?

Answer

Hi... It is a RMI compiler,to create stubs and skeletons of
a application

Is This Answer Correct ?

4 Yes

2 No

Question { 5784 }

What is serialization and de-serialization ?

Answer

Hi...
Serialization: It is the process of storing the object
state into permanent device like harddisc,external file
system.

De-serialization:It is the process of getting the object
state, just reverse of the serialization.

Is This Answer Correct ?

1 Yes

0 No

Question { Verizon, 9188 }

What is synchronization?

Answer

Hi...
Synchronization:It is a mechanism of controlling the shared
resource againist the multiple processes inorder to provide
the concurrent access.

Is This Answer Correct ?

3 Yes

0 No

Question { 6551 }

Name the method to find, if a thread is active or not?

Answer

Hi... u can use "public void isActive();"method in the
Thread class

Is This Answer Correct ?

1 Yes

2 No