Cognizant Fullstack Java Developer Interview Questions and Answers

1)Driffience between Abstract class &
Interface.
-abstract class
represents property
&
behaviour of an object
whereas
interface
represents
behaviour
of an object.
2)Driffience between equal() vs ==operator.
equal() is
an object class method
whereas
equal() of string class
override
the object class equal().
3)can we use pointer's in Java.
Not explicitly but implicitly we can use pointer's in java.
Dynamic m/m refers with help of pointer's but java does not support the pointer's.
when we r creating an object in java refrence varaible of an object holds the identity that is nothing but an implicit pointer that holds an unique identity of an object.
4)How we can print object ID.
-Object ID printed with help of object class which is a service provider class having 9().
5)what is object class.
-it is a super class of all predefined & userdefined class.
6)Write a prog to get name of main thread in java.
-class A
{
psvm(String args [])
{
s.o.pln(Thread.currentThread().getName());
}
}
7)length vs length()
-length
is
data menmber
of proxy class
whereas
length() is a string class().

Q1. Explain JVM in ur own language.
Ans. 
JVM is an abstract machine that executes Java bytecode.
• JVM stands for Java Virtual Machine.

• It is responsible for interpreting and executing Java bytecode.

• JVM provides platform independence to Java programs.

• It has its own memory management system and garbage collector.

• JVM can be implemented on different operating systems.

• Examples of JVM languages include Java, Kotlin, and Scala.
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Q2. Exlplaing Multhreading.
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