Core Java Interview Questions, Answers for Freshers and Experienced asked in various Company Job Interviews

Core Java Interview Questions

Questions Answers Views Company eMail

printstream class method println() is calling using System class and its static object out .how it is explain any one in detail with example ?

TCS,

1 5324

whats the purposr of using serialization?

6 9480

how to one war file class to another war file class?

2032

suppose in a class there is a code like this: { Set hs=new Hashset(); hs.add(new Emp("kathy",1000)); hs.add(new Emp("kathy",2000)); } how can u avoid the above code in your class as set won't allow duplicate objects?

3 6512

what is meant by UP& DOWN casting in java?

6 14304

how can we import the user defined package without classpath?

CSC, Infosys,

1 7678

Write a java program to find the route that connects between Red and Green Cells. General Rules for traversal 1. You can traverse from one cell to another vertically, horizontally or diagonally. 2. You cannot traverse through Black cells. 3. There should be only one Red and Green cell and at least one of each should be present. Otherwise the array is invalid. 4. You cannot revisit a cell that you have already traversed. 5. The maze need not be in the same as given in the above example

2556

For ease of programming you can consider the maze as a 2D array with colors represented by below integer and characters (in capital letters). • B - Black • W -White • G- Green • R- Red R B W B W W W W W W B W B B W W W W W W W B W B W W W B W W W W B B W W W B W W W B W W B B B B W B W B W W B W W W B W W W B B B W W B W W W B W W B W B W W W B W B W W W W B B W W W W B W W W W W G Shortest Route Problem: • Solution that finds the shortest Route between Red and Green  White will have 1 Weight.  Red and Green carry no weights.  Shortest path is the path with less weight when you add up the weights in the path.

1991

what is j2se

3 6246

we have two threads..both the threads are reading the data.. is there any need of synchronization there?...justify it?

IBM,

4 8216

what is unreachable code problem in multiple catch statements

3 6472

where lives in jvm

5 8743

What is "Java Native Interface" and how to use it?

IBM,

1 5913

What is the diff. b/w Interfaces & Abstract class?

Ericsson,

6 10289

Which of these methods belong to Thread & Object class? join, yield, sleep, wait, notify

Ericsson,

3 9987

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Un-Answered Questions { Core Java }

What are different exception types exceptions available in java ?

960

What is the purpose of the wait(), notify(), and notifyall() methods in java programming?

1020

Why pass by reference is not possible in java?

977

Can we override the overloaded method?

1074

What does the “static” keyword mean? Can you override private or static method in java?

1055

What is the difference between processes and threads?

1006

What is a line separator in java?

941

Is it possible to use string in the switch case?

1009

What is generic type?

987

What is a Presistent Object?

1193

Is an array a vector?

981

What is logical variable?

939

What is core java used for?

1066

What is the structure of java?

978

Can we have multiple classes in single file ?

1026

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