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 5472

whats the purposr of using serialization?

6 9926

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

2151

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 6767

what is meant by UP& DOWN casting in java?

6 14721

how can we import the user defined package without classpath?

CSC, Infosys,

1 7855

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

2639

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.

2061

what is j2se

3 6543

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

IBM,

4 8524

what is unreachable code problem in multiple catch statements

3 6711

where lives in jvm

5 9122

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

IBM,

1 6092

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

Ericsson,

6 10664

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

Ericsson,

3 10302

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Un-Answered Questions { Core Java }

What are synchronized blocks in java?

1283

What is unmodifiable collection in java?

976

What is the format specifier?

998

Does java support function overloading, pointers, structures, unions or linked lists?

1168

How to implement a multithreaded applet?

2735

How big is a 64 bit float?

1074

Explain inheritance in java?

1066

What is derived datatype?

1276

Is int a class in java?

1031

Can a hashset contain duplicates java?

1029

How to find the largest value from the given array.

1072

What is a function in programming?

1102

When should I use a singleton?

1103

Why hashcode is used in java?

1031

Is java an ide?

1033

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